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).

packages/server/src/routes/repos.ts

@@ -0,0 +1,56 @@
+import type { FastifyInstance, FastifyReply } from 'fastify';
+import type { CreateRepoRequest, RepoResponse, ReposListResponse, UpdateRepoRequest } from '@arboretum/shared';
+import type { WorktreeManager } from '../core/worktree-manager.js';
+
+/** Mappe une erreur du manager (statusCode + code) vers une réponse REST normalisée. */
+export function sendManagerError(reply: FastifyReply, err: unknown): FastifyReply {
+  const e = err as { statusCode?: number; code?: string; message?: string };
+  return reply.status(e.statusCode ?? 500).send({ error: { code: e.code ?? 'INTERNAL', message: e.message ?? 'Internal error' } });
+}
+
+export function registerRepoRoutes(app: FastifyInstance, wt: WorktreeManager): void {
+  app.get('/api/v1/repos', async (): Promise<ReposListResponse> => ({ repos: await wt.listRepos() }));
+
+  app.post('/api/v1/repos', async (req, reply) => {
+    const body = req.body as Partial<CreateRepoRequest> | null;
+    if (!body || typeof body.path !== 'string') {
+      return reply.status(400).send({ error: { code: 'BAD_REQUEST', message: 'path (absolute) is required' } });
+    }
+    try {
+      const repo = await wt.addRepo({
+        path: body.path,
+        ...(body.label !== undefined ? { label: body.label } : {}),
+        ...(body.postCreateHooks !== undefined ? { postCreateHooks: body.postCreateHooks } : {}),
+        ...(body.preTrust !== undefined ? { preTrust: body.preTrust } : {}),
+      });
+      const res: RepoResponse = { repo };
+      return reply.status(201).send(res);
+    } catch (err) {
+      return sendManagerError(reply, err);
+    }
+  });
+
+  app.patch('/api/v1/repos/:id', async (req, reply) => {
+    const { id } = req.params as { id: string };
+    const body = (req.body as Partial<UpdateRepoRequest> | null) ?? {};
+    try {
+      const repo = await wt.updateRepo(id, {
+        ...(body.label !== undefined ? { label: body.label } : {}),
+        ...(body.postCreateHooks !== undefined ? { postCreateHooks: body.postCreateHooks } : {}),
+        ...(body.preTrust !== undefined ? { preTrust: body.preTrust } : {}),
+      });
+      const res: RepoResponse = { repo };
+      return reply.send(res);
+    } catch (err) {
+      return sendManagerError(reply, err);
+    }
+  });
+
+  app.delete('/api/v1/repos/:id', async (req, reply) => {
+    const { id } = req.params as { id: string };
+    if (!wt.removeRepo(id)) {
+      return reply.status(404).send({ error: { code: 'NOT_FOUND', message: 'No repo with this id' } });
+    }
+    return reply.send({ ok: true });
+  });
+}