feat: cap-aware autoscaler + token-gated whole-instance tag reset (operator feedback)

Autoscaler (agent 2026-07-02.5): the buffer-occupancy signal alone would peg
downloaders at DL_MAX while the bandwidth CAP — not concurrency — is the real
constraint (8 streams sharing 8 MB/s move no more data than 4). Growth is now
gated on the pipe having headroom (net < 85% of cap) and a pipe pinned at the
cap (>= 95%) sheds streams down to 3; dead band prevents flapping. The UI hint
says 'holding at the bandwidth cap' and /status reports bw_capped, so the
behavior is legible without tests that need the ML stack.

Reset content tagging: stays a FULL-instance reset (operator's call), but now
lives in a fenced 'Danger zone' section on Cleanup and the apply is gated by a
preview-derived confirm token (mirrors the Tier-C bulk-delete pattern — stale
counts are rejected server-side). Copy no longer claims suggestions repopulate:
it says plainly the heads' training examples are deleted and re-tagging starts
fresh. Moved out of TagMaintenanceCard into DangerZoneCard.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

frontend/src/components/settings/DangerZoneCard.vue

@@ -0,0 +1,122 @@
+<template>
+  <MaintenanceTile
+    icon="mdi-nuke"
+    title="Reset content tagging (whole instance)"
+    blurb="Delete ALL general/character tags and their applications — a start-over. Requires a confirmation code."
+    destructive
+  >
+    <p class="text-body-2 mb-2">
+      Deletes every <code>general</code> and <code>character</code> tag and
+      removes them from every image — <strong>including the examples the
+      tagging heads learned from</strong>. Suggestions will <strong>not</strong>
+      repopulate on their own: you re-tag from scratch, and the heads retrain
+      from your new tags as they accumulate. Fandoms and series (with their
+      page order) are kept.
+    </p>
+    <v-alert type="error" variant="tonal" density="compact" class="mb-3">
+      Irreversible — no undo except restoring a DB backup
+      (Settings → Maintenance → Backup). Back one up first.
+    </v-alert>
+
+    <v-btn
+      color="accent" variant="flat" rounded="pill"
+      prepend-icon="mdi-magnify"
+      :loading="loadingPreview"
+      class="mb-3"
+      @click="onPreview"
+    >Preview content-tag reset</v-btn>
+
+    <div v-if="preview">
+      <p class="text-body-2 mb-2">
+        <strong>{{ preview.count }}</strong> content tag(s)
+        <span v-for="(n, k) in preview.by_kind" :key="k" class="fc-muted">
+          ({{ k }}: {{ n }})&nbsp;
+        </span>
+        across <strong>{{ preview.applications }}</strong> image
+        application(s).
+      </p>
+      <SampleNameGrid
+        v-if="preview.sample_names?.length"
+        :names="preview.sample_names" class="mb-3"
+      />
+      <template v-if="preview.count">
+        <p class="text-body-2 mb-2">
+          To arm the reset, type the confirmation code
+          <code class="fc-code">{{ preview.confirm }}</code> below.
+        </p>
+        <div class="d-flex align-center mb-1" style="gap: 12px">
+          <v-text-field
+            v-model="typed" density="compact" hide-details variant="outlined"
+            label="Confirmation code" style="max-width: 200px"
+            autocomplete="off" spellcheck="false"
+          />
+          <v-btn
+            color="error" variant="flat" rounded="pill"
+            prepend-icon="mdi-delete-alert"
+            :disabled="typed !== preview.confirm"
+            :loading="committing"
+            @click="onCommit"
+          >Delete {{ preview.count }} tag(s) +
+            {{ preview.applications }} application(s)</v-btn>
+        </div>
+        <p class="fc-muted text-caption mb-0">
+          The code is derived from the counts above — if tagging changes
+          between preview and apply, the server rejects the stale code.
+        </p>
+      </template>
+    </div>
+  </MaintenanceTile>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+
+import { toast } from '../../utils/toast.js'
+import MaintenanceTile from '../common/MaintenanceTile.vue'
+import SampleNameGrid from '../common/SampleNameGrid.vue'
+import { useAdminStore } from '../../stores/admin.js'
+
+const store = useAdminStore()
+const preview = ref(null)
+const loadingPreview = ref(false)
+const committing = ref(false)
+const typed = ref('')
+
+async function onPreview() {
+  loadingPreview.value = true
+  typed.value = ''
+  try {
+    preview.value = await store.resetContentTagging({ dryRun: true })
+  } catch (e) {
+    toast({ text: `Preview failed: ${e.message}`, type: 'error' })
+  } finally {
+    loadingPreview.value = false
+  }
+}
+
+async function onCommit() {
+  committing.value = true
+  try {
+    const res = await store.resetContentTagging({
+      dryRun: false, confirm: typed.value,
+    })
+    toast({ text: `Deleted ${res.deleted} content tag(s) — re-tagging starts fresh`, type: 'success' })
+    preview.value = null
+    typed.value = ''
+  } catch (e) {
+    toast({ text: `Reset rejected: ${e.message}`, type: 'error' })
+  } finally {
+    committing.value = false
+  }
+}
+</script>
+
+<style scoped>
+.fc-muted { color: rgb(var(--v-theme-on-surface-variant)); }
+.fc-code {
+  background: rgb(var(--v-theme-surface-light));
+  border-radius: 4px; padding: 2px 8px;
+  font-family: 'JetBrains Mono', monospace; font-weight: 700;
+  letter-spacing: 0.06em;
+}
+</style>

frontend/src/components/settings/TagMaintenanceCard.vue

@@ -42,56 +42,6 @@
     </div>
   </MaintenanceTile>
 
-  <MaintenanceTile
-    icon="mdi-tag-multiple"
-    title="Reset content tagging"
-    blurb="Delete all general/character tags to re-tag from scratch."
-    destructive
-  >
-    <p class="text-body-2 mb-2">
-      Deletes every <code>general</code> and <code>character</code> tag and
-      removes them from every image, so you can re-tag from scratch with the
-      auto-suggest. <strong>Fandoms and series (with their page order) are
-      kept</strong>, and each image's saved predictions are untouched — open
-      an image and its suggestions reappear.
-    </p>
-    <v-alert type="warning" variant="tonal" density="compact" class="mb-3">
-      Irreversible — there's no undo except restoring a DB backup.
-      Back one up first (Settings → Maintenance → Backup).
-    </v-alert>
-
-    <v-btn
-      color="accent" variant="flat" rounded="pill"
-      prepend-icon="mdi-magnify"
-      :loading="loadingResetPreview"
-      class="mb-3"
-      @click="onResetPreview"
-    >Preview content-tag reset</v-btn>
-
-    <div v-if="resetPreview">
-      <p class="text-body-2 mb-2">
-        <strong>{{ resetPreview.count }}</strong> content tag(s)
-        <span v-for="(n, k) in resetPreview.by_kind" :key="k" class="fc-muted">
-          ({{ k }}: {{ n }})&nbsp;
-        </span>
-        across <strong>{{ resetPreview.applications }}</strong> image
-        application(s).
-      </p>
-      <SampleNameGrid
-        v-if="resetPreview.sample_names?.length"
-        :names="resetPreview.sample_names" class="mb-3"
-      />
-      <v-btn
-        color="error" variant="flat" rounded="pill"
-        prepend-icon="mdi-delete-alert"
-        :disabled="!resetPreview.count"
-        :loading="resetCommitting"
-        @click="onResetCommit"
-      >Delete {{ resetPreview.count }} content tag(s) +
-        {{ resetPreview.applications }} application(s)</v-btn>
-    </div>
-  </MaintenanceTile>
-
   <MaintenanceTile
     icon="mdi-format-letter-case"
     title="Standardize tag casing"
@@ -169,16 +119,6 @@ const {
   emptyPreview: (r) => ({ count: 0, sample_names: r.sample_names || [] }),
 })
 
-// Reset content tagging (general + character).
-const {
-  previewData: resetPreview, previewing: loadingResetPreview,
-  committing: resetCommitting, runPreview: onResetPreview, runCommit: onResetCommit,
-} = usePreviewCommit({
-  preview: () => store.resetContentTagging({ dryRun: true }),
-  commit: () => store.resetContentTagging({ dryRun: false }),
-  emptyPreview: { count: 0, by_kind: {}, applications: 0, sample_names: [] },
-})
-
 // Standardize casing. The apply DISPATCHES a self-resuming background task (no
 // poll-until-done — that would falsely report complete after the first chunk),
 // so there's no emptyPreview: leave the projection up; a truthy normResult means

frontend/src/stores/admin.js

@@ -101,8 +101,10 @@ export const useAdminStore = defineStore('admin', () => {
     })
   }
 
-  // Destructive: deletes ALL general + character tags so the operator can
-  // re-tag from scratch via auto-suggest. fandom + series preserved.
+  // Destructive whole-instance reset: deletes ALL general + character tags AND
+  // their applications (the heads' training data included) — fandom + series
+  // preserved. dry-run returns a `confirm` token; the apply must pass it back
+  // ({ dryRun: false, confirm }) or the server rejects it.
   function resetContentTagging(opts = {}) {
     return _dryRunPost('/api/admin/tags/reset-content', opts)
   }

frontend/src/views/CleanupView.vue

@@ -39,6 +39,17 @@
         <TagMaintenanceCard />
       </div>
     </section>
+
+    <section class="fc-section fc-danger">
+      <h3 class="fc-section__title fc-danger__title">Danger zone</h3>
+      <p class="fc-section__hint">
+        Whole-instance resets. Each needs a fresh preview and a typed
+        confirmation code.
+      </p>
+      <div class="fc-tile-grid">
+        <DangerZoneCard />
+      </div>
+    </section>
   </div>
 </template>
 
@@ -50,6 +61,7 @@ import PostMaintenanceCard from '../components/settings/PostMaintenanceCard.vue'
 import VideoDedupCard from '../components/settings/VideoDedupCard.vue'
 import GatedPurgeCard from '../components/settings/GatedPurgeCard.vue'
 import TagMaintenanceCard from '../components/settings/TagMaintenanceCard.vue'
+import DangerZoneCard from '../components/settings/DangerZoneCard.vue'
 </script>
 
 <style scoped>
@@ -75,4 +87,12 @@ import TagMaintenanceCard from '../components/settings/TagMaintenanceCard.vue'
   gap: 14px;
   align-items: start;
 }
+/* Danger zone: visually fenced off from routine cleanup so the reset can't
+   be mistaken for maintenance. */
+.fc-danger {
+  border-top: 1px solid rgba(var(--v-theme-error), 0.45);
+  padding-top: 18px;
+  margin-top: 36px;
+}
+.fc-danger__title { color: rgb(var(--v-theme-error)); }
 </style>