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/server/src/ws/gateway.ts

@@ -5,6 +5,7 @@ import {
   PROTOCOL_VERSION,
   encodeBinaryFrame,
   parseClientMessage,
+  type GroupSummary,
   type RepoSummary,
   type ServerMessage,
   type SessionSummary,
@@ -13,6 +14,7 @@ import {
 import type { ClientBinding, PtyManager } from '../core/pty-manager.js';
 import type { DiscoveryService } from '../core/discovery-service.js';
 import type { WorktreeManager } from '../core/worktree-manager.js';
+import type { GroupManager } from '../core/group-manager.js';
 
 const HEARTBEAT_MS = 30_000;
 
@@ -26,6 +28,7 @@ export function registerWsGateway(
   manager: PtyManager,
   discovery: DiscoveryService,
   worktrees: WorktreeManager,
+  groups: GroupManager,
   serverVersion: string,
 ): void {
   app.get('/ws', { websocket: true }, (socket: WebSocket, req) => {
@@ -35,6 +38,7 @@ export function registerWsGateway(
     let helloDone = false;
     let subscribedSessions = false;
     let subscribedWorktrees = false;
+    let subscribedGroups = false;
     let alive = true;
 
     const send = (msg: ServerMessage): void => {
@@ -66,6 +70,12 @@ export function registerWsGateway(
     const onWorktreeRemoved = (e: { repoId: string; path: string }): void => {
       if (subscribedWorktrees) send({ type: 'worktree_removed', ...e });
     };
+    const onGroupUpdate = (group: GroupSummary): void => {
+      if (subscribedGroups) send({ type: 'group_update', group });
+    };
+    const onGroupRemoved = (groupId: string): void => {
+      if (subscribedGroups) send({ type: 'group_removed', groupId });
+    };
     manager.on('session_update', onSessionUpdate);
     manager.on('session_exit', onSessionExit);
     discovery.on('discovery_update', onDiscoveryUpdate);
@@ -73,6 +83,8 @@ export function registerWsGateway(
     worktrees.on('repo_removed', onRepoRemoved);
     worktrees.on('worktree_update', onWorktreeUpdate);
     worktrees.on('worktree_removed', onWorktreeRemoved);
+    groups.on('group_update', onGroupUpdate);
+    groups.on('group_removed', onGroupRemoved);
 
     const heartbeat = setInterval(() => {
       if (!alive) {
@@ -111,6 +123,7 @@ export function registerWsGateway(
         case 'sub': {
           subscribedSessions = msg.topics.includes('sessions');
           subscribedWorktrees = msg.topics.includes('worktrees');
+          subscribedGroups = msg.topics.includes('groups');
           return;
         }
         case 'attach': {
@@ -202,6 +215,8 @@ export function registerWsGateway(
       worktrees.off('repo_removed', onRepoRemoved);
       worktrees.off('worktree_update', onWorktreeUpdate);
       worktrees.off('worktree_removed', onWorktreeRemoved);
+      groups.off('group_update', onGroupUpdate);
+      groups.off('group_removed', onGroupRemoved);
       for (const [, st] of channels) manager.detach(st.sessionId, st.binding);
       channels.clear();
     });