feat: groupes de travail (P5)

Ajoute la notion de groupe — collection nommée de repos (membership légère
persistée, many-to-many) — pour piloter plusieurs repos en simultané :

- DB : migration #5 (tables groups + group_repos, FK ON DELETE CASCADE).
- GroupManager (synchrone, EventEmitter) + routes REST /api/v1/groups ;
  ne persiste que la membership, worktrees/sessions filtrés par repoId côté client.
- Protocole : GroupSummary, DTOs, topic WS « groups », events group_update/removed
  (additifs, PROTOCOL_VERSION inchangé).
- Web : store groups, GroupsListView, GroupView (réutilise RepoSection),
  grille multi-terminaux (TerminalGrid/TerminalCell), action « feature cross-repo »
  (orchestration client, tolérante aux échecs partiels), routes + i18n EN/FR.
- Tests : group-manager.test.ts + extension protocol.test.ts ; acceptance-p5.mjs.

packages/web/src/components/CrossRepoFeatureModal.vue

@@ -0,0 +1,122 @@
+<template>
+  <div class="fixed inset-0 z-50 flex items-center justify-center bg-black/60 p-4" @click.self="emit('close')">
+    <div class="flex max-h-[90vh] w-full max-w-lg flex-col gap-3 overflow-y-auto rounded-lg border border-zinc-800 bg-zinc-900 p-4">
+      <header class="flex items-center gap-2">
+        <h2 class="font-semibold text-zinc-100">{{ t('crossRepo.title') }}</h2>
+        <button class="btn ml-auto text-xs" @click="emit('close')">{{ t('crossRepo.close') }}</button>
+      </header>
+      <p class="text-xs text-zinc-500">{{ t('crossRepo.intro') }}</p>
+
+      <form class="flex flex-col gap-3" @submit.prevent="onSubmit">
+        <label class="flex flex-col gap-1 text-xs text-zinc-400">
+          {{ t('crossRepo.branchLabel') }}
+          <input v-model="branch" class="input font-mono" :placeholder="t('crossRepo.branchPlaceholder')" required />
+        </label>
+        <div class="flex flex-wrap items-end gap-3">
+          <label class="flex items-center gap-1.5 text-xs text-zinc-400">
+            <input v-model="newBranch" type="checkbox" /> {{ t('crossRepo.newBranch') }}
+          </label>
+          <label class="flex flex-col gap-1 text-xs text-zinc-400">
+            {{ t('crossRepo.baseRefLabel') }}
+            <input v-model="baseRef" class="input font-mono" placeholder="HEAD" />
+          </label>
+          <label class="flex flex-col gap-1 text-xs text-zinc-400">
+            {{ t('crossRepo.startLabel') }}
+            <select v-model="startSession" class="input">
+              <option :value="null">{{ t('crossRepo.startNone') }}</option>
+              <option value="claude">claude</option>
+              <option value="bash">bash</option>
+            </select>
+          </label>
+        </div>
+
+        <div class="flex flex-col gap-1 text-xs text-zinc-400">
+          {{ t('crossRepo.reposLabel') }}
+          <div class="flex flex-col gap-1">
+            <label
+              v-for="repo in repos"
+              :key="repo.id"
+              class="flex items-center gap-2 rounded border border-zinc-800 bg-zinc-950/40 px-2 py-1"
+            >
+              <input v-model="selectedRepoIds" type="checkbox" :value="repo.id" :disabled="running" />
+              <span class="flex-1 text-zinc-300">{{ repo.label }}</span>
+              <span v-if="results[repo.id]" class="text-[11px]" :class="statusClass(repo.id)">
+                {{ statusText(repo.id) }}
+              </span>
+            </label>
+          </div>
+        </div>
+
+        <div class="flex items-center gap-2">
+          <button type="submit" class="btn-primary" :disabled="running || branch.trim() === '' || selectedRepoIds.length === 0">
+            {{ running ? t('crossRepo.creating') : t('crossRepo.create', { n: selectedRepoIds.length }) }}
+          </button>
+          <button v-if="hasFailures && !running" type="button" class="btn text-xs" @click="retryFailed">
+            {{ t('crossRepo.retryFailed') }}
+          </button>
+        </div>
+      </form>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed, ref } from 'vue';
+import { useI18n } from 'vue-i18n';
+import type { RepoSummary } from '@arboretum/shared';
+import { useGroupsStore, type CrossRepoResult } from '../stores/groups';
+
+const props = defineProps<{ repos: RepoSummary[] }>();
+const emit = defineEmits<{ close: [] }>();
+
+const { t } = useI18n();
+const groups = useGroupsStore();
+
+const branch = ref('');
+const newBranch = ref(true);
+const baseRef = ref('');
+const startSession = ref<'claude' | 'bash' | null>(null);
+const selectedRepoIds = ref<string[]>(props.repos.map((r) => r.id));
+const results = ref<Record<string, CrossRepoResult>>({});
+const running = ref(false);
+
+const hasFailures = computed(() => Object.values(results.value).some((r) => r.status === 'error'));
+
+function statusClass(repoId: string): string {
+  return results.value[repoId]?.status === 'ok' ? 'text-emerald-400' : 'text-red-400';
+}
+function statusText(repoId: string): string {
+  const r = results.value[repoId];
+  if (!r) return '';
+  return r.status === 'ok' ? t('crossRepo.ok') : `${t('crossRepo.error')}: ${r.message ?? ''}`;
+}
+
+async function run(repoIds: string[]): Promise<void> {
+  if (repoIds.length === 0) return;
+  running.value = true;
+  for (const id of repoIds) delete results.value[id];
+  try {
+    await groups.createCrossRepoFeature(
+      repoIds,
+      {
+        branch: branch.value.trim(),
+        newBranch: newBranch.value,
+        ...(baseRef.value.trim() ? { baseRef: baseRef.value.trim() } : {}),
+        startSession: startSession.value,
+      },
+      (result) => {
+        results.value = { ...results.value, [result.repoId]: result };
+      },
+    );
+  } finally {
+    running.value = false;
+  }
+}
+
+function onSubmit(): void {
+  void run([...selectedRepoIds.value]);
+}
+function retryFailed(): void {
+  void run(Object.values(results.value).filter((r) => r.status === 'error').map((r) => r.repoId));
+}
+</script>