P3-A: worktrees multi-repo & cycle de vie (backend)

Enregistrement de repos et gestion de leurs worktrees git, source de vérité
= git (worktrees dérivés + cache court par repo), corrélation worktree ↔
sessions par cwd, mutations sérialisées par repo.

- shared: RepoSummary, PostCreateHook, WorktreeSummary, WorktreeGitStatus ;
  messages WS repo_update/worktree_update/*_removed ; topic sub 'worktrees'
  (+ parseClientMessage) ; DTOs REST repos/worktrees.
- db: migration id:3 (table repos).
- core/git.ts: couche git sûre (execFile, jamais de shell, -- avant chemins,
  GIT_OPTIONAL_LOCKS=0), parseWorktreePorcelain, list/add/remove/prune/status/
  ahead-behind, validation branche + chemin.
- core/claude-trust.ts: pré-trust atomique de ~/.claude.json (spike S3).
- core/worktree-manager.ts: repos CRUD, create (worktree add + pré-trust +
  hooks post-create + startSession optionnel), adopt, delete (garde-fous 409
  dirty / 400 main / 409 session live), prune ; events.
- routes/repos.ts + routes/worktrees.ts, câblage app.ts, gateway topic worktrees.
- tests: git (repos tmp réels), claude-trust, worktree-manager (146 verts).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/server/src/ws/gateway.ts

@@ -5,11 +5,14 @@ import {
   PROTOCOL_VERSION,
   encodeBinaryFrame,
   parseClientMessage,
+  type RepoSummary,
   type ServerMessage,
   type SessionSummary,
+  type WorktreeSummary,
 } from '@arboretum/shared';
 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';
 
 const HEARTBEAT_MS = 30_000;
 
@@ -22,6 +25,7 @@ export function registerWsGateway(
   app: FastifyInstance,
   manager: PtyManager,
   discovery: DiscoveryService,
+  worktrees: WorktreeManager,
   serverVersion: string,
 ): void {
   app.get('/ws', { websocket: true }, (socket: WebSocket, req) => {
@@ -30,6 +34,7 @@ export function registerWsGateway(
     let nextChannel = 1;
     let helloDone = false;
     let subscribedSessions = false;
+    let subscribedWorktrees = false;
     let alive = true;
 
     const send = (msg: ServerMessage): void => {
@@ -49,9 +54,25 @@ export function registerWsGateway(
     const onDiscoveryUpdate = (session: SessionSummary): void => {
       if (subscribedSessions) send({ type: 'session_update', session });
     };
+    const onRepoUpdate = (repo: RepoSummary): void => {
+      if (subscribedWorktrees) send({ type: 'repo_update', repo });
+    };
+    const onRepoRemoved = (repoId: string): void => {
+      if (subscribedWorktrees) send({ type: 'repo_removed', repoId });
+    };
+    const onWorktreeUpdate = (e: { repoId: string; worktree: WorktreeSummary }): void => {
+      if (subscribedWorktrees) send({ type: 'worktree_update', ...e });
+    };
+    const onWorktreeRemoved = (e: { repoId: string; path: string }): void => {
+      if (subscribedWorktrees) send({ type: 'worktree_removed', ...e });
+    };
     manager.on('session_update', onSessionUpdate);
     manager.on('session_exit', onSessionExit);
     discovery.on('discovery_update', onDiscoveryUpdate);
+    worktrees.on('repo_update', onRepoUpdate);
+    worktrees.on('repo_removed', onRepoRemoved);
+    worktrees.on('worktree_update', onWorktreeUpdate);
+    worktrees.on('worktree_removed', onWorktreeRemoved);
 
     const heartbeat = setInterval(() => {
       if (!alive) {
@@ -89,6 +110,7 @@ export function registerWsGateway(
         }
         case 'sub': {
           subscribedSessions = msg.topics.includes('sessions');
+          subscribedWorktrees = msg.topics.includes('worktrees');
           return;
         }
         case 'attach': {
@@ -160,6 +182,10 @@ export function registerWsGateway(
       manager.off('session_update', onSessionUpdate);
       manager.off('session_exit', onSessionExit);
       discovery.off('discovery_update', onDiscoveryUpdate);
+      worktrees.off('repo_update', onRepoUpdate);
+      worktrees.off('repo_removed', onRepoRemoved);
+      worktrees.off('worktree_update', onWorktreeUpdate);
+      worktrees.off('worktree_removed', onWorktreeRemoved);
       for (const [, st] of channels) manager.detach(st.sessionId, st.binding);
       channels.clear();
     });