v2 : couche données complète + shell + primitives communes

- stores/collective.ts (état local-first, gabarits, import/export, seeds)
  + stores/decisions.ts (cycle de vie complet : capture→chemin→fenêtres→
  sessions→cristallisation→épreuve du réel→révocation)
- data/templates.ts : 7 gabarits (Page blanche observatoire-d'abord,
  5 points de départ, Institution symétrique)
- composables useFeed (13 sections du Fil en sélecteurs purs) + useSearch
  (index unique Cmd+K/Q0)
- shell : layouts default/bare, app.vue mince, useMood v2 (Source/Margelle/
  Nappe/Minuit), sceau 井 = logo, LdWorkspaceSelector avec finalité A1,
  LdAvatarStack (premier/second lieu), LdCountdown (suspension striée)
- 338 tests vitest verts, npm run build zéro erreur

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/app/components/common/LdAvatarStack.vue

@@ -0,0 +1,100 @@
+<script setup lang="ts">
+// <!-- ld-v2 --> Stacked initials avatars — deterministic tint from id, -8px overlap.
+// origin glyphs: 'computed' = full dot (concerné·e en premier lieu),
+// 'declared' = raised hand (en second lieu). Tap → parent shows inclusion reason.
+import type { Person } from '~/types/domain'
+
+const props = withDefaults(defineProps<{
+  people: { person: Person; origin?: 'computed' | 'declared'; reason?: string }[]
+  max?: number
+  size?: number
+}>(), { max: 6, size: 30 })
+
+const emit = defineEmits<{ (e: 'tap', entry: { person: Person; origin?: string; reason?: string }): void }>()
+
+const visible = computed(() => props.people.slice(0, props.max))
+const overflow = computed(() => Math.max(0, props.people.length - props.max))
+
+function initials(name: string): string {
+  return name.split(/[\s-]+/).map(w => w[0] ?? '').join('').slice(0, 2).toUpperCase()
+}
+function tint(id: string): string {
+  let h = 0
+  for (let i = 0; i < id.length; i++) h = (h * 31 + id.charCodeAt(i)) % 360
+  return `oklch(0.72 0.09 ${h})`
+}
+</script>
+
+<template>
+  <!-- ld-v2 -->
+  <div class="ld-avatars" :style="{ '--av-size': size + 'px' }">
+    <button
+      v-for="entry in visible"
+      :key="entry.person.id"
+      class="ld-avatars__item"
+      :style="{ background: tint(entry.person.id) }"
+      :title="entry.reason ? `${entry.person.displayName} — ${entry.reason}` : entry.person.displayName"
+      type="button"
+      @click="emit('tap', entry)"
+    >
+      <span>{{ initials(entry.person.displayName) }}</span>
+      <span v-if="entry.origin === 'declared'" class="ld-avatars__glyph">
+        <UIcon name="i-lucide-hand" />
+      </span>
+      <span v-else-if="entry.origin === 'computed'" class="ld-avatars__dot" />
+    </button>
+    <span v-if="overflow > 0" class="ld-avatars__more">+{{ overflow }}</span>
+  </div>
+</template>
+
+<style scoped>
+.ld-avatars { display: inline-flex; align-items: center; }
+.ld-avatars__item {
+  position: relative;
+  width: var(--av-size);
+  height: var(--av-size);
+  border-radius: 50%;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(var(--av-size) * 0.36);
+  font-weight: 700;
+  color: rgba(255, 255, 255, 0.95);
+  margin-left: -8px;
+  box-shadow: 0 0 0 2px var(--mood-surface);
+  cursor: pointer;
+  transition: transform 0.1s ease;
+}
+.ld-avatars__item:first-child { margin-left: 0; }
+.ld-avatars__item:hover { transform: translateY(-1px); z-index: 1; }
+.ld-avatars__glyph {
+  position: absolute;
+  right: -3px;
+  bottom: -3px;
+  width: calc(var(--av-size) * 0.48);
+  height: calc(var(--av-size) * 0.48);
+  border-radius: 50%;
+  background: var(--mood-surface);
+  color: var(--mood-accent);
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(var(--av-size) * 0.3);
+}
+.ld-avatars__dot {
+  position: absolute;
+  right: -1px;
+  bottom: -1px;
+  width: calc(var(--av-size) * 0.28);
+  height: calc(var(--av-size) * 0.28);
+  border-radius: 50%;
+  background: var(--mood-accent);
+  box-shadow: 0 0 0 2px var(--mood-surface);
+}
+.ld-avatars__more {
+  margin-left: 0.4rem;
+  font-size: 0.8125rem;
+  font-weight: 700;
+  color: var(--mood-text-muted);
+}
+</style>