feat: worker lanes move to the System tab, in the roster's own idiom (4295)

Operator, 2026-09-23: *"where is the setting surface to set the number of
each kind of worker? we have a system view under settings but no options to
be set here"* — then *"move it to system tab and improve the view to be more
inline with other UI elements."*

They went looking under System and found a read-only roster. The card's own
first cut argued that a control had no place on a tab about things being
broken; that was wrong twice over. Half these lanes are optional and off by
DESIGN, so "not running" is the normal state someone comes here to change —
and a tab that only reports is a tab you leave in order to act somewhere else.

So it is the roster's second half now, and built out of the same parts: the
pane above says what is running, this one says how hard. Dot, name, detail,
numbers on the right; the controls take the place the roster gives to latency.
It was a bordered card wrapping a v-table, which is what made it read as
bolted on.

- The row styles move from SystemHealthTab's scoped block into app.css, so
  the second pane IS the first one's idiom rather than imitating it. A copy
  would have drifted the first time either was touched.
- Lane state uses the roster's four dots. A lane that is off reads grey, never
  red: colouring an intended state as a fault is how an indicator stops being
  read.
- The card owns its own polling. On Activity it rode that tab's 3s queue
  timer; System has none, so moving without this would have shown an empty
  pane to anyone who opened System first. 15s and `document.hidden`-guarded —
  it is a dial, not a live meter, and v-window keeps a hidden tab mounted.
- The table header carried the column names, so each control now labels
  itself: `slots · cap N`, `auto`, `on`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LVjrnpQjRgHdvq95rASoiR

frontend/src/components/settings/SystemActivityTab.vue

@@ -17,11 +17,6 @@
       </v-card-text>
     </v-card>
 
-    <!-- The dial for the pane above (milestone 422). Directly beneath it
-         because the two are read together: you see a queue growing and give
-         that lane more slots without leaving the pane. -->
-    <WorkerLanesCard />
-
     <!-- The non-Celery halves of the app (2026-07-02): the GPU agent does the
          majority of processing and downloads feed the library — Activity is
          the whole-app pulse, not just the worker queues. -->
@@ -177,7 +172,6 @@ import { useSystemActivityStore } from '../../stores/systemActivity.js'
 import { formatRelative as fmtRelative } from '../../utils/date.js'
 import ErrorDetailModal from '../common/ErrorDetailModal.vue'
 import QueuesTable from './QueuesTable.vue'
-import WorkerLanesCard from './WorkerLanesCard.vue'
 import CardHeading from '../common/CardHeading.vue'
 import GpuActivityPanel from './GpuActivityPanel.vue'
 import DownloadsActivityPanel from './DownloadsActivityPanel.vue'
@@ -242,7 +236,6 @@ function pollQueues() {
   store.loadQueues()
   store.loadWorkers()
   store.loadRecentRuns()
-  store.loadLanes()
 }
 function pollFailures() {
   if (document.hidden) return

frontend/src/components/settings/SystemHealthTab.vue

@@ -65,6 +65,17 @@
       then neither, and an indicator that reddened on every update would stop
       being read.
     </p>
+
+    <!-- The dial for the roster above (milestone 422). Moved here from
+         Activity on 2026-09-23 at the operator's ask: they went looking for
+         "how many workers of each kind" under System, which is where the
+         question belongs — the roster says what is running, and this says how
+         hard. Its own first cut argued the opposite, that a control has no
+         place on a tab about things being broken. That was wrong twice over:
+         half these lanes are optional and off by DESIGN, so "not running" is
+         the normal state the operator comes here to change, and a tab that
+         only reports is a tab you leave to go act somewhere else. -->
+    <WorkerLanesCard />
   </div>
 </template>
 
@@ -73,6 +84,7 @@ import { onMounted } from 'vue'
 
 import { useSystemHealthStore } from '../../stores/systemHealth.js'
 import { formatRelative } from '../../utils/date.js'
+import WorkerLanesCard from './WorkerLanesCard.vue'
 
 const store = useSystemHealthStore()
 
@@ -91,38 +103,3 @@ function kindLabel(kind) {
 // One refresh on open, so arriving at the tab doesn't wait out the nav's tick.
 onMounted(() => { store.refresh() })
 </script>
-
-<style scoped>
-.fc-sys__lede, .fc-sys__muted, .fc-sys__checked, .fc-sys__foot {
-  color: rgb(var(--v-theme-on-surface) / 0.66);
-}
-.fc-sys__checked { font-size: 0.78rem; }
-.fc-sys__card { background: rgb(var(--v-theme-on-surface) / 0.04); }
-
-.fc-sys__row {
-  display: flex; align-items: center; gap: 12px;
-  padding: 12px 16px;
-  border-bottom: 1px solid rgb(var(--v-theme-on-surface) / 0.08);
-}
-.fc-sys__row:last-child { border-bottom: 0; }
-
-.fc-sys__dot { width: 9px; height: 9px; border-radius: 50%; flex: 0 0 auto; }
-.fc-sys__dot--ok      { background: rgb(var(--v-theme-success)); }
-.fc-sys__dot--stale   { background: rgb(var(--v-theme-warning)); }
-.fc-sys__dot--down    { background: rgb(var(--v-theme-error)); }
-.fc-sys__dot--unknown { background: rgb(var(--v-theme-on-surface) / 0.35); }
-
-.fc-sys__body { min-width: 0; flex: 1 1 auto; }
-.fc-sys__name { font-weight: 600; }
-.fc-sys__kind {
-  margin-left: 8px; font-weight: 400; font-size: 0.72rem; text-transform: uppercase;
-  letter-spacing: 0.04em; color: rgb(var(--v-theme-on-surface) / 0.5);
-}
-.fc-sys__detail { font-size: 0.82rem; color: rgb(var(--v-theme-on-surface) / 0.72); }
-
-.fc-sys__meta {
-  text-align: right; font-size: 0.75rem; flex: 0 0 auto;
-  font-variant-numeric: tabular-nums; color: rgb(var(--v-theme-on-surface) / 0.6);
-}
-.fc-sys__queues { opacity: 0.75; }
-</style>

frontend/src/components/settings/WorkerLanesCard.vue

@@ -1,210 +1,194 @@
 <template>
-  <!-- Milestone 422 step 4. The dial for how much work each lane does, beside
+  <!-- Milestone 422 step 4, restyled and moved to the System tab on
-       the "Queues + workers" pane that shows the backlog it is reacting to —
+       2026-09-23 (operator: "move it to system tab and improve the view to be
-       you see the queue growing and adjust the lane without leaving the pane.
+       more inline with other UI elements").
 
-       Deliberately NOT in the System tab. That one (milestone 365) answers "is
+       It is the roster's second half. The pane above answers "what is
-       everything running", and every control on it would be about a thing that
+       running"; this answers "how hard" — so it is built out of the SAME row
-       is broken. This is about a thing that is working and should work harder. -->
+       idiom rather than a bordered card wrapping a v-table, which is what it
-  <v-card class="mb-4">
+       was and what made it read as bolted on. Dot, name, detail, numbers on
-    <CardHeading icon="mdi-tune-variant" title="Worker lanes">
+       the right; the controls take the place the roster gives to latency. -->
+  <div class="fc-lanes">
+    <div class="d-flex align-center mb-1 mt-8">
+      <span class="fc-section-h">Worker lanes</span>
       <v-spacer />
-      <span class="text-caption fc-muted">
+      <span class="fc-sys__checked">
-        updated {{ formatRelative(store.lanes?.fetched_at) }}
+        {{ store.lanes ? `updated ${formatRelative(store.lanes.fetched_at)}` : 'reading…' }}
       </span>
-    </CardHeading>
+    </div>
 
-    <v-card-text>
+    <p class="fc-sys__lede text-body-2 mb-5">
-      <p class="fc-section__hint mb-3">
+      Slots are how many tasks a lane runs at once. Changes reach the running
-        Slots are how many tasks a lane runs at once. Changes apply to the
+      worker immediately and survive a restart, so this is the dial to reach
-        running worker immediately and survive a restart.
+      for when a queue above is growing faster than it drains.
-      </p>
+    </p>
 
-      <v-alert
+    <v-alert
-        v-if="notice"
+      v-if="notice"
-        :type="notice.type" variant="tonal" density="compact"
+      :type="notice.type" variant="tonal" density="compact"
-        class="mb-3" closable
+      class="mb-4" closable
-        @click:close="notice = null"
+      @click:close="notice = null"
-      >
+    >
-        {{ notice.text }}
+      {{ notice.text }}
-      </v-alert>
+    </v-alert>
 
-      <v-table density="compact">
+    <v-card variant="flat" class="fc-sys__card">
-        <thead>
+      <div v-if="!lanesList.length" class="pa-6 text-center fc-sys__muted">
-          <tr>
+        Still reading the lanes — this fills in on the first check.
-            <th>Lane</th>
+      </div>
-            <th>Queues</th>
-            <th class="text-right">Pending</th>
-            <th class="text-right">Busy</th>
-            <th style="width: 200px;">Slots</th>
-            <th class="text-right">Auto</th>
-            <th class="text-right">On</th>
-          </tr>
-        </thead>
-        <tbody>
-          <tr v-for="lane in lanesList" :key="lane.name">
-            <td>
-              <div class="d-flex align-center" style="gap: 6px;">
-                <span>{{ lane.display_name }}</span>
-                <!-- Said in the row, not only in the warning below. Someone
-                     scanning the table to work out why a lane is off should
-                     not have to enable it to find out it was never required. -->
-                <v-chip v-if="lane.optional" size="x-small" variant="tonal">
-                  optional
-                </v-chip>
-              </div>
-              <!-- Not present is NOT zero slots — it is "nothing answered".
-                   Saying "stopped" here would be a verdict drawn from an
-                   unswept read, and the operator would go looking for a crash
-                   that has not happened. -->
-              <div v-if="!lane.live.present" class="text-caption fc-muted">
-                not answering
-              </div>
-              <div v-else-if="lane.live.replicas > 1" class="text-caption fc-muted">
-                {{ lane.live.replicas }} replicas
-              </div>
-              <!-- The operator asked for a lane held at full for a long time
-                   to TRIGGER growth. It reports instead: extra slots do not
-                   make a long task finish sooner, so scaling on this would
-                   spend memory to change nothing. Seeing the lane is wedged
-                   on one slow job is the useful half, and it cannot mislead
-                   a lane into growing for the wrong reason. -->
-              <div v-if="laneStuckFor(lane)" class="text-caption text-warning">
-                all slots busy for {{ laneStuckFor(lane) }}
-              </div>
-            </td>
 
-            <td class="text-caption fc-muted">{{ lane.queues.join(', ') }}</td>
+      <div v-for="lane in lanesList" :key="lane.name" class="fc-sys__row">
+        <span class="fc-sys__dot" :class="`fc-sys__dot--${laneState(lane)}`" />
 
-            <!-- depth + reserved. LLEN alone reads 0 while a worker holds
+        <div class="fc-sys__body">
-                 prefetched tasks in memory, which is the number that would
+          <div class="fc-sys__name">
-                 make someone think a lane was idle while it was buried. -->
+            {{ lane.display_name }}
-            <td class="text-right">
+            <!-- Said in the row rather than only in the advisory below.
-              <span v-if="lane.pending === null" class="fc-muted">—</span>
+                 Someone scanning to work out why a lane is off should not have
-              <span v-else>{{ lane.pending }}</span>
+                 to turn it on to find out it was never required. -->
-            </td>
+            <span class="fc-sys__kind">{{ lane.optional ? 'optional' : 'lane' }}</span>
-
+          </div>
-            <td class="text-right">
+          <!-- "Not answering" is NOT zero slots — it is "nothing replied".
-              <span v-if="!lane.live.present" class="fc-muted">—</span>
+               Calling it stopped would be a verdict drawn from an unswept
-              <span v-else>{{ lane.live.active }} / {{ lane.live.pool ?? '?' }}</span>
+               read, and would send the operator looking for a crash that has
-            </td>
+               not happened. -->
-
+          <div class="fc-sys__detail">{{ laneDetail(lane) }}</div>
-            <td>
+          <!-- The operator asked for a lane held at full for a long time to
-              <div class="d-flex align-center" style="gap: 4px;">
+               TRIGGER growth. It reports instead: extra slots do not make a
-                <v-btn
+               long task finish sooner, so scaling on this would spend memory
-                  icon="mdi-minus" size="x-small" variant="text"
+               to change nothing. Seeing the lane wedged on one slow job is the
-                  :disabled="busy === lane.name || lane.slots <= 0"
+               useful half, and it cannot mislead a lane into growing for the
-                  :aria-label="`Fewer slots for ${lane.display_name}`"
+               wrong reason. -->
-                  @click="step(lane, -1)"
+          <div v-if="laneStuckFor(lane)" class="fc-sys__detail text-warning">
-                />
+            all slots busy for {{ laneStuckFor(lane) }}
-                <span class="fc-slots">{{ lane.slots }}</span>
+          </div>
-                <v-btn
-                  icon="mdi-plus" size="x-small" variant="text"
-                  :disabled="busy === lane.name || lane.slots >= lane.slots_cap"
-                  :aria-label="`More slots for ${lane.display_name}`"
-                  @click="step(lane, 1)"
-                />
-                <!-- The REASON a higher value is unavailable, always on screen.
-                     A greyed control with no explanation reads as a bug, and
-                     the ceiling is the one number here the operator cannot
-                     change — so it has to justify itself. -->
-                <span class="text-caption fc-muted ml-1">
-                  cap {{ lane.slots_cap }}<template v-if="lane.slots_cap >= lane.ceiling">
-                    · max {{ lane.ceiling }}{{ lane.memory_bound ? ' (memory)' : '' }}
-                  </template>
-                </span>
-              </div>
-            </td>
-
-            <!-- The autoscaler is the one control here that acts without
-                 being asked, so it is a separate switch from `On` rather than
-                 a mode folded into it, and it is off until someone opts this
-                 particular lane in.
-
-                 Turning it ON needs room to grow into; turning it OFF never
-                 does. Disabling the whole switch at cap == slots would strand
-                 an already-autoscaling lane as soon as someone raised its
-                 floor to the cap, with the control that would undo it greyed
-                 out. And the reason is on screen, for the same reason the
-                 ceiling justifies itself below: a greyed control with no
-                 explanation reads as a bug. -->
-            <td class="text-right">
-              <v-switch
-                :model-value="lane.autoscale"
-                density="compact" hide-details color="accent"
-                :disabled="busy === lane.name || (!lane.autoscale && !canGrow(lane))"
-                :aria-label="`Let ${lane.display_name} grow itself`"
-                @update:model-value="setAutoscale(lane, $event)"
-              />
-              <div v-if="!canGrow(lane)" class="text-caption fc-muted">
-                raise the cap
-              </div>
-            </td>
-
-            <td class="text-right">
-              <v-switch
-                :model-value="lane.enabled"
-                density="compact" hide-details color="accent"
-                :disabled="busy === lane.name"
-                :aria-label="`Enable ${lane.display_name}`"
-                @update:model-value="toggle(lane, $event)"
-              />
-            </td>
-          </tr>
-        </tbody>
-      </v-table>
-
-      <!-- What an optional, off lane will cost BEFORE it is switched on.
-           Every number here comes from the lane payload, and `measured`
-           travels with them — an estimate is labelled rather than rounded
-           into something that reads like a fact. The previous version of this
-           said "a few GB", which told the operator nothing they could plan
-           with and was not sourced from anything. -->
-      <v-alert
-        v-for="lane in offOptionalLanes" :key="`advisory-${lane.name}`"
-        type="info" variant="tonal" density="compact" class="mt-3"
-      >
-        <div class="font-weight-medium mb-1">
-          {{ lane.display_name }} is optional and currently off
         </div>
-        <p class="mb-2">
+
-          It computes image embeddings on the CPU — what similarity search,
+        <div class="fc-sys__meta">
-          duplicate grouping and tag suggestions are built on. You only need it
+          <!-- depth + reserved. LLEN alone reads 0 while a worker holds
-          if you are <em>not</em> running the GPU agent, which does the same
+               prefetched tasks in memory, which is the number that would make
-          work faster.
+               someone think a buried lane was idle. -->
-        </p>
+          <div>{{ lane.pending === null ? '—' : lane.pending }} pending</div>
-        <p class="mb-1">Turning it on downloads, once:</p>
+          <div v-if="lane.live.present">
-        <ul class="mb-2">
+            {{ lane.live.active }} / {{ lane.live.pool ?? '?' }} busy
-          <li v-for="m in lane.models" :key="m.repo">
+          </div>
-            <code>{{ m.repo }}</code> —
+          <div class="fc-sys__queues">{{ lane.queues.join(', ') }}</div>
-            {{ approx(m.measured) }}{{ gb(m.download_bytes) }} to download,
+        </div>
-            and about {{ gb(m.resident_bytes) }} of RAM for
+
-            <strong>each</strong> slot while it runs.
+        <div class="fc-lanes__controls">
-          </li>
+          <div class="fc-lanes__control">
-        </ul>
+            <div class="d-flex align-center">
-        <p class="mb-0 text-caption">
+              <v-btn
-          Each slot loads its own copy, which is why this container caps the
+                icon="mdi-minus" size="x-small" variant="text"
-          lane at {{ lane.ceiling }}.
+                :disabled="busy === lane.name || lane.slots <= 0"
-          <template v-if="lane.ceiling === 0">
+                :aria-label="`Fewer slots for ${lane.display_name}`"
-            It has too little memory to run this at all.
+                @click="step(lane, -1)"
-          </template>
+              />
-        </p>
+              <span class="fc-lanes__slots">{{ lane.slots }}</span>
-      </v-alert>
+              <v-btn
-    </v-card-text>
+                icon="mdi-plus" size="x-small" variant="text"
-  </v-card>
+                :disabled="busy === lane.name || lane.slots >= lane.slots_cap"
+                :aria-label="`More slots for ${lane.display_name}`"
+                @click="step(lane, 1)"
+              />
+            </div>
+            <!-- The REASON a higher value is unavailable, always on screen. A
+                 greyed control with no explanation reads as a bug, and the
+                 ceiling is the one number here the operator cannot change — so
+                 it has to justify itself. -->
+            <div class="fc-lanes__label">
+              slots · cap {{ lane.slots_cap }}<template
+                v-if="lane.slots_cap >= lane.ceiling"
+              >
+                · max {{ lane.ceiling }}{{ lane.memory_bound ? ' (memory)' : '' }}
+              </template>
+            </div>
+          </div>
+
+          <!-- The autoscaler is the one control here that acts without being
+               asked, so it is a separate switch from `On` rather than a mode
+               folded into it, and it is off until someone opts this particular
+               lane in.
+
+               Turning it ON needs room to grow into; turning it OFF never
+               does. Disabling the whole switch at cap == slots would strand an
+               already-autoscaling lane the moment someone raised its floor to
+               the cap, with the control that would undo it greyed out. -->
+          <div class="fc-lanes__control">
+            <v-switch
+              :model-value="lane.autoscale"
+              density="compact" hide-details color="accent"
+              :disabled="busy === lane.name || (!lane.autoscale && !canGrow(lane))"
+              :aria-label="`Let ${lane.display_name} grow itself`"
+              @update:model-value="setAutoscale(lane, $event)"
+            />
+            <div class="fc-lanes__label">
+              {{ canGrow(lane) ? 'auto' : 'raise the cap' }}
+            </div>
+          </div>
+
+          <div class="fc-lanes__control">
+            <v-switch
+              :model-value="lane.enabled"
+              density="compact" hide-details color="accent"
+              :disabled="busy === lane.name"
+              :aria-label="`Enable ${lane.display_name}`"
+              @update:model-value="toggle(lane, $event)"
+            />
+            <div class="fc-lanes__label">on</div>
+          </div>
+        </div>
+      </div>
+    </v-card>
+
+    <!-- What an optional, off lane will cost BEFORE it is switched on. Every
+         number comes from the lane payload, and `measured` travels with them —
+         an estimate is labelled rather than rounded into something that reads
+         like a fact. An earlier version said "a few GB", which told the
+         operator nothing they could plan with and was sourced from nothing. -->
+    <v-alert
+      v-for="lane in offOptionalLanes" :key="`advisory-${lane.name}`"
+      type="info" variant="tonal" density="compact" class="mt-4"
+    >
+      <div class="font-weight-medium mb-1">
+        {{ lane.display_name }} is optional and currently off
+      </div>
+      <p class="mb-2">
+        It computes image embeddings on the CPU — what similarity search,
+        duplicate grouping and tag suggestions are built on. You only need it
+        if you are <em>not</em> running the GPU agent, which does the same work
+        faster.
+      </p>
+      <p class="mb-1">Turning it on downloads, once:</p>
+      <ul class="mb-2">
+        <li v-for="m in lane.models" :key="m.repo">
+          <code>{{ m.repo }}</code> —
+          {{ approx(m.measured) }}{{ gb(m.download_bytes) }} to download, and
+          about {{ gb(m.resident_bytes) }} of RAM for
+          <strong>each</strong> slot while it runs.
+        </li>
+      </ul>
+      <p class="mb-0 text-caption">
+        Each slot loads its own copy, which is why this container caps the lane
+        at {{ lane.ceiling }}.
+        <template v-if="lane.ceiling === 0">
+          It has too little memory to run this at all.
+        </template>
+      </p>
+    </v-alert>
+  </div>
 </template>
 
 <script setup>
-import { computed, ref } from 'vue'
+import { computed, onMounted, onUnmounted, ref } from 'vue'
 
 import { laneStuckFor, useSystemActivityStore } from '../../stores/systemActivity.js'
 import { formatRelative } from '../../utils/date.js'
-import CardHeading from '../common/CardHeading.vue'
 
 const store = useSystemActivityStore()
 
-// Which lane is mid-write. Per-lane rather than a global flag so adjusting
+// Which lane is mid-write. Per-lane rather than a global flag so adjusting one
-// one lane does not freeze the others.
+// lane does not freeze the others.
 const busy = ref(null)
 const notice = ref(null)
 
@@ -218,6 +202,51 @@ const offOptionalLanes = computed(() =>
   lanesList.value.filter((l) => l.optional && !l.enabled && l.models?.length),
 )
 
+// This card owns its own reads now. On Activity it rode that tab's 3s queue
+// poll; the System tab has no timer at all — the roster is fed by TopNav's
+// store, which knows nothing about lanes — so moving without this would have
+// shown an empty pane to anyone who opened System first.
+//
+// 15s, not 3s: `/api/system/workers` costs a broker round trip, and this pane
+// is a dial rather than a live meter. `document.hidden` because v-window keeps
+// a visited tab MOUNTED, so the interval keeps firing behind Maintenance and
+// behind a backgrounded browser tab.
+const POLL_MS = 15000
+let pollId = null
+
+function poll() {
+  if (document.hidden) return
+  store.loadLanes()
+}
+
+onMounted(() => {
+  store.loadLanes()
+  pollId = setInterval(poll, POLL_MS)
+})
+onUnmounted(() => { clearInterval(pollId) })
+
+// Same four states the roster's dots mean, so one legend covers both panes.
+// A lane that is off reads `unknown` (grey), never `down` (red): half of these
+// are optional and off by design, and colouring the intended state as a fault
+// is how an indicator stops being read.
+function laneState(lane) {
+  if (!lane.live.present) return lane.enabled ? 'down' : 'unknown'
+  if (!lane.enabled) return 'unknown'
+  if (laneStuckFor(lane)) return 'stale'
+  return 'ok'
+}
+
+function laneDetail(lane) {
+  if (!lane.live.present) {
+    return lane.enabled
+      ? 'not answering — it is switched on, so it should be'
+      : 'not answering, and switched off'
+  }
+  if (!lane.enabled) return 'running but not consuming its queues'
+  if (lane.live.replicas > 1) return `running on ${lane.live.replicas} replicas`
+  return 'running'
+}
+
 function gb(bytes) {
   return `${(bytes / 1024 ** 3).toFixed(1)} GB`
 }
@@ -240,7 +269,7 @@ async function apply(lane, fields) {
       notice.value = {
         type: 'info',
         text: `${lane.display_name} is on. Downloading its model now — `
-          + 'watch progress in Queues + workers above. It only happens once.',
+          + 'watch progress under Activity. It only happens once.',
       }
     } else if (reply && reply.applied === false) {
       notice.value = {
@@ -257,9 +286,9 @@ async function apply(lane, fields) {
     //
     // `e.body`, not `e.detail`: ApiError puts the parsed response on `.body`
     // and sets `.message` to the short `error` key. Reading the wrong one
-    // falls back to that key and shows the operator the word "refused" with
+    // falls back to that key and shows the operator the word "refused" with no
-    // no reason — which is exactly the greyed-control-with-no-explanation
+    // reason — which is exactly the greyed-control-with-no-explanation failure
-    // failure this line exists to prevent.
+    // this line exists to prevent.
     notice.value = { type: 'error', text: e.body?.detail || e.message }
   } finally {
     busy.value = null
@@ -287,9 +316,24 @@ function setAutoscale(lane, value) {
 </script>
 
 <style scoped>
+/* The controls occupy the slot the roster gives to latency and last-seen, so
+   they are right-aligned and fixed-width — a row whose switches slide left as
+   a lane's numbers change is the thing that made the old table feel unrelated
+   to the pane above it. */
+.fc-lanes__controls {
+  display: flex; align-items: flex-start; gap: 4px; flex: 0 0 auto;
+}
+.fc-lanes__control { text-align: center; min-width: 56px; }
+.fc-lanes__control:first-child { min-width: 132px; }
+
+.fc-lanes__label {
+  font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.04em;
+  color: rgb(var(--v-theme-on-surface) / 0.5); white-space: nowrap;
+}
+
 /* Fixed width so the number does not shift the +/- buttons as it changes
    between one and two digits. */
-.fc-slots {
+.fc-lanes__slots {
   display: inline-block;
   min-width: 1.75em;
   text-align: center;

frontend/src/styles/app.css

@@ -132,3 +132,50 @@
   backdrop-filter: blur(2px);
   -webkit-backdrop-filter: blur(2px);
 }
+
+/* The System tab's row idiom (operator 2026-09-23: "improve the view to be
+   more inline with other UI elements").
+
+   The roster (milestone 365) and the worker lanes (milestone 422) sit on the
+   same tab and answer the two halves of one question — what is running, and
+   how hard. They were built months apart and looked it: one a flat list of
+   dotted rows, the other a bordered card wrapping a v-table. Lifting these out
+   of SystemHealthTab's scoped block is what lets the second pane BE the first
+   one's idiom rather than imitate it — a copy would drift the first time
+   either was touched.
+
+   `fc-sys__` rather than a new prefix because the roster's markup already uses
+   these names; renaming would have been churn in the file that is not
+   changing. */
+.fc-sys__lede, .fc-sys__muted, .fc-sys__checked, .fc-sys__foot {
+  color: rgb(var(--v-theme-on-surface) / 0.66);
+}
+.fc-sys__checked { font-size: 0.78rem; }
+.fc-sys__card { background: rgb(var(--v-theme-on-surface) / 0.04); }
+
+.fc-sys__row {
+  display: flex; align-items: center; gap: 12px;
+  padding: 12px 16px;
+  border-bottom: 1px solid rgb(var(--v-theme-on-surface) / 0.08);
+}
+.fc-sys__row:last-child { border-bottom: 0; }
+
+.fc-sys__dot { width: 9px; height: 9px; border-radius: 50%; flex: 0 0 auto; }
+.fc-sys__dot--ok      { background: rgb(var(--v-theme-success)); }
+.fc-sys__dot--stale   { background: rgb(var(--v-theme-warning)); }
+.fc-sys__dot--down    { background: rgb(var(--v-theme-error)); }
+.fc-sys__dot--unknown { background: rgb(var(--v-theme-on-surface) / 0.35); }
+
+.fc-sys__body { min-width: 0; flex: 1 1 auto; }
+.fc-sys__name { font-weight: 600; }
+.fc-sys__kind {
+  margin-left: 8px; font-weight: 400; font-size: 0.72rem; text-transform: uppercase;
+  letter-spacing: 0.04em; color: rgb(var(--v-theme-on-surface) / 0.5);
+}
+.fc-sys__detail { font-size: 0.82rem; color: rgb(var(--v-theme-on-surface) / 0.72); }
+
+.fc-sys__meta {
+  text-align: right; font-size: 0.75rem; flex: 0 0 auto;
+  font-variant-numeric: tabular-nums; color: rgb(var(--v-theme-on-surface) / 0.6);
+}
+.fc-sys__queues { opacity: 0.75; }