P3-C: dashboard worktree-first + acceptance P3 (MVP complet)

Vue racine consolidée : repos → worktrees avec état git ET état de session
corrélé. Complète le MVP (P2 découverte/reprise + P3-A worktrees + P3-B états fins).

- web/lib/ws-client: abonnement multi-topics (sessions + worktrees), subscribeWorktrees.
- web/stores/worktrees: repos + worktrees, CRUD, temps réel (repo_update/worktree_*).
- web/views/DashboardView (route racine /), components RepoSection + WorktreeCard ;
  SessionStateBadge réutilisé pour l'état des sessions corrélées.
- router: / = dashboard, /sessions = liste à plat (sessions hors worktree), nav croisée.
- i18n EN/FR (dashboard/repos/worktrees).
- fix: @xterm/headless est CommonJS → chargé via createRequire (l'import nommé ESM
  échouait sous Node natif, masqué par esbuild en test) ; détecté par l'acceptation.
- scripts/acceptance-p3.mjs: repo git tmp → enregistrement, worktree + hook, broadcast
  WS worktree_update, corrélation session bash, suppression (409 sans force, 200 avec).

Vérifs : typecheck, 159 tests, build (vue-tsc), acceptations P1/P2/P3 ALL GREEN.

packages/web/src/components/RepoSection.vue

@@ -0,0 +1,93 @@
+<template>
+  <section class="flex flex-col gap-2 rounded-lg border border-zinc-800 bg-zinc-900/50 p-3">
+    <header class="flex items-center gap-2">
+      <h2 class="font-semibold text-zinc-100">{{ repo.label }}</h2>
+      <span v-if="!repo.valid" class="badge bg-red-950 text-red-400">{{ t('repos.invalid') }}</span>
+      <span class="truncate font-mono text-xs text-zinc-500" :title="repo.path">{{ repo.path }}</span>
+      <div class="ml-auto flex items-center gap-2">
+        <button class="btn text-xs" @click="creating = !creating">{{ t('worktrees.new') }}</button>
+        <button class="btn text-xs" :disabled="busy" @click="onPrune">{{ t('worktrees.prune') }}</button>
+        <button class="btn-danger text-xs" @click="onRemove">{{ t('repos.remove') }}</button>
+      </div>
+    </header>
+
+    <form v-if="creating" class="flex flex-wrap items-end gap-2 rounded border border-zinc-800 bg-zinc-950/40 p-2" @submit.prevent="onCreate">
+      <label class="flex flex-1 flex-col gap-1 text-xs text-zinc-400">
+        {{ t('worktrees.branch') }}
+        <input v-model="branch" class="input font-mono" :placeholder="repo.defaultBranch ? `feature/…` : 'feature/…'" required />
+      </label>
+      <label class="flex flex-col gap-1 text-xs text-zinc-400">
+        {{ t('worktrees.start') }}
+        <select v-model="startSession" class="input">
+          <option :value="null">{{ t('worktrees.startNone') }}</option>
+          <option value="claude">claude</option>
+          <option value="bash">bash</option>
+        </select>
+      </label>
+      <label class="flex items-center gap-1 text-xs text-zinc-400"><input v-model="newBranch" type="checkbox" /> {{ t('worktrees.newBranch') }}</label>
+      <button type="submit" class="btn-primary text-xs" :disabled="busy || branch.trim() === ''">
+        {{ busy ? t('worktrees.creating') : t('worktrees.create') }}
+      </button>
+    </form>
+    <p v-if="error" class="text-sm text-red-400">{{ error }}</p>
+
+    <div class="flex flex-col gap-1.5">
+      <WorktreeCard v-for="w in worktrees" :key="w.path" :worktree="w" />
+    </div>
+  </section>
+</template>
+
+<script setup lang="ts">
+import { computed, ref } from 'vue';
+import { useI18n } from 'vue-i18n';
+import type { RepoSummary } from '@arboretum/shared';
+import { useWorktreesStore } from '../stores/worktrees';
+import WorktreeCard from './WorktreeCard.vue';
+
+const props = defineProps<{ repo: RepoSummary }>();
+const { t } = useI18n();
+const store = useWorktreesStore();
+
+const worktrees = computed(() => store.worktreesForRepo(props.repo.id));
+const creating = ref(false);
+const branch = ref('');
+const newBranch = ref(true);
+const startSession = ref<'claude' | 'bash' | null>(null);
+const busy = ref(false);
+const error = ref<string | null>(null);
+
+async function onCreate(): Promise<void> {
+  busy.value = true;
+  error.value = null;
+  try {
+    await store.createWorktree(props.repo.id, { branch: branch.value.trim(), newBranch: newBranch.value, startSession: startSession.value });
+    branch.value = '';
+    creating.value = false;
+  } catch (err) {
+    error.value = err instanceof Error ? err.message : String(err);
+  } finally {
+    busy.value = false;
+  }
+}
+
+async function onPrune(): Promise<void> {
+  busy.value = true;
+  error.value = null;
+  try {
+    await store.prune(props.repo.id);
+  } catch (err) {
+    error.value = err instanceof Error ? err.message : String(err);
+  } finally {
+    busy.value = false;
+  }
+}
+
+async function onRemove(): Promise<void> {
+  error.value = null;
+  try {
+    await store.removeRepo(props.repo.id);
+  } catch (err) {
+    error.value = err instanceof Error ? err.message : String(err);
+  }
+}
+</script>