feat(projects): cap milestone bars at 10, open work first

Roundtable's card rendered ~35 milestone bars and ran several viewport-heights
tall, so one tile dwarfed the grid and stopped being scannable — which is the
whole job of a card (#2391).

Now 10 bars, ordered OPEN WORK FIRST and newest first within each group, with
"+25 more milestones" beneath.

Ordering by recency alone would have been wrong, and the operator's call was to
lead with open work: a long-running project's oldest milestones are usually its
finished ones, so the ten most recent could easily have been ten completed bars
while the three in flight were the ones hidden. A card answers "what is
happening", not "what happened".

Three details that are the actual work:

- The palette index is captured from the FULL list before slicing. Colour keyed
  to visible position would have recoloured every bar on the card each time a
  milestone closed or was added.
- Computed once per load into a Map rather than called from the template. A
  helper invoked inside v-for re-runs on every render, and this one sorts.
- The overflow notice is plain text, not a link. The whole card already
  navigates to the project, and a link nested inside a clickable region is a
  trap for keyboard and screen-reader users.

Saying the count matters more than the cap: a list that simply stops reads as a
rendering bug, while a count reads as a summary.

Payload is unchanged — the API still returns every milestone. Capping
server-side would also need the total to travel with it, or the "+N" has
nothing to count from; not worth it while the response is two queries (#2384).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UaYUaouG9jjhATyuxCKrQs

frontend/src/views/ProjectListView.vue

@@ -113,6 +113,45 @@ function truncate(text: string | null, max = 120): string {
   return text.length > max ? text.slice(0, max) + "..." : text;
 }
 
+// A card is a glance, not a report. Roundtable had ~35 milestones and its tile
+// ran several viewport-heights tall, which made the grid unreadable (#2391).
+const MAX_MILESTONE_BARS = 10;
+
+interface MilestoneBar extends MilestoneSummary {
+  /** Position in the FULL list, so a bar keeps its colour when another
+   *  milestone is added or finishes. Tying the palette to the visible index
+   *  would recolour the card every time work closed. */
+  paletteIndex: number;
+}
+
+/** Bars to draw per project, plus how many were withheld.
+ *
+ * Ordered OPEN WORK FIRST, newest first. Recency alone would be wrong here: a
+ * long-running project's oldest milestones are usually its finished ones, so
+ * showing 10 completed bars while hiding the 3 in flight is worse than showing
+ * nothing. What the card is for is "what is happening", not "what happened".
+ *
+ * Computed once per load rather than called from the template — a helper in a
+ * v-for is re-run on every render, and this one sorts.
+ */
+const milestoneBars = computed(() => {
+  const byProject = new Map<number, { bars: MilestoneBar[]; hidden: number }>();
+  for (const project of projects.value) {
+    const all = project.summary?.milestone_summary ?? [];
+    const indexed: MilestoneBar[] = all.map((ms, i) => ({ ...ms, paletteIndex: i }));
+    const newestFirst = (a: MilestoneBar, b: MilestoneBar) => b.id - a.id;
+    const ordered = [
+      ...indexed.filter((m) => m.pct < 100).sort(newestFirst),
+      ...indexed.filter((m) => m.pct >= 100).sort(newestFirst),
+    ];
+    byProject.set(project.id, {
+      bars: ordered.slice(0, MAX_MILESTONE_BARS),
+      hidden: Math.max(0, ordered.length - MAX_MILESTONE_BARS),
+    });
+  }
+  return byProject;
+});
+
 function overallPct(project: Project): { total: number; pct: number } {
   const counts = project.summary?.task_counts;
   if (!counts) return { total: 0, pct: 0 };
@@ -185,11 +224,11 @@ function overallPct(project: Project): { total: number; pct: number } {
 
         <!-- Milestone progress bars -->
         <div
-          v-if="project.summary?.milestone_summary?.length"
+          v-if="milestoneBars.get(project.id)?.bars.length"
           class="milestone-bars"
         >
           <div
-            v-for="(ms, i) in project.summary.milestone_summary"
+            v-for="ms in milestoneBars.get(project.id)!.bars"
             :key="ms.id"
             class="milestone-bar-row"
             :title="`${ms.title} — ${ms.pct}% (${ms.completed}/${ms.total} tasks)`"
@@ -198,11 +237,23 @@ function overallPct(project: Project): { total: number; pct: number } {
             <div class="milestone-bar-track">
               <div
                 class="milestone-bar-fill"
-                :style="{ width: ms.pct + '%', background: milestoneColor(i) }"
+                :style="{ width: ms.pct + '%', background: milestoneColor(ms.paletteIndex) }"
               ></div>
             </div>
             <span class="milestone-bar-pct">{{ ms.pct }}%</span>
           </div>
+          <!-- Say what is withheld. A list that simply stops reads as a
+               rendering bug; a count reads as a summary. Plain text, not a
+               link: the whole card already navigates to this project, and a
+               link nested inside a clickable region is a trap for keyboard
+               and screen-reader users. -->
+          <span
+            v-if="milestoneBars.get(project.id)!.hidden"
+            class="milestone-more"
+          >
+            +{{ milestoneBars.get(project.id)!.hidden }}
+            {{ milestoneBars.get(project.id)!.hidden === 1 ? 'more milestone' : 'more milestones' }}
+          </span>
         </div>
 
         <div class="card-footer">
@@ -492,6 +543,14 @@ function overallPct(project: Project): { total: number; pct: number } {
   text-align: right;
 }
 
+/* Deliberately quiet — it is a footnote about what is not shown, not another
+   row competing with the bars above it. */
+.milestone-more {
+  color: var(--color-text-muted);
+  font-size: var(--fs-size-tiny);
+  padding-top: 0.15rem;
+}
+
 .card-footer {
   margin-top: auto;
 }