feat(vscode): extension VS Code native (intégration native, pas un webview)

Nouveau workspace packages/vscode (git-arboretum, privé, non publié sur npm), client REST/WS
réutilisant @arboretum/shared. Auth Authorization: Bearer sur REST et l'upgrade WS (via `ws`) ;
un client Node sans en-tête Origin passe le check Origin strict du serveur.

- Arbres temps réel : Repositories (repos → worktrees → sessions) et Groups, via le WebSocket.
- Terminaux natifs (vscode.Pseudoterminal) pour attacher/observer une session — rendu et
  scrollback de VS Code ; décodage UTF-8 streaming + comptabilité ACK dans des modules purs.
- Status bar (compteur waiting) + notifications natives sur passage en waiting, réponses Yes/No
  via la commande WS answer.
- Mutations git (create worktree, commit, push, promote), start/kill/hide/resume/fork, session
  de groupe ; conscience du workspace (reveal + start/create here).
- Bundle esbuild (format cjs, external vscode) inlinant @arboretum/shared → VSIX autonome.
  Logique réutilisable sans import vscode → testée par vitest (19 tests).
- CI : .gitea/workflows/vscode-release.yml package le VSIX sur tag vscode-vX.Y.Z (artefact +
  asset de release best-effort). build:vscode hors du build principal (comme le site).
- spikes/s5-vscode/STUDY.md : décision de conception (GO phasé A→D), marquée implémentée.

packages/vscode/test/rest-client.test.ts

@@ -0,0 +1,51 @@
+import { describe, expect, it, vi } from 'vitest';
+import { RestClient, RestError } from '../src/api/rest-client.js';
+
+type Captured = { url: string; init: RequestInit };
+
+function fakeFetch(response: { ok: boolean; status: number; body: unknown }, captured: Captured[]) {
+  return vi.fn(async (url: string, init: RequestInit) => {
+    captured.push({ url, init });
+    return {
+      ok: response.ok,
+      status: response.status,
+      json: async () => response.body,
+    } as unknown as Response;
+  }) as unknown as typeof fetch;
+}
+
+describe('RestClient', () => {
+  it('appelle /api/v1/auth/me avec le header Bearer', async () => {
+    const captured: Captured[] = [];
+    const rest = new RestClient(
+      { baseUrl: 'http://127.0.0.1:7317/', token: 'arb_secret' },
+      fakeFetch({ ok: true, status: 200, body: { ok: true, tokenId: 't', tokenLabel: 'l', serverVersion: '1.8.0' } }, captured),
+    );
+    const me = await rest.me();
+    expect(me.serverVersion).toBe('1.8.0');
+    expect(captured[0]?.url).toBe('http://127.0.0.1:7317/api/v1/auth/me');
+    const headers = captured[0]?.init.headers as Record<string, string>;
+    expect(headers.Authorization).toBe('Bearer arb_secret');
+  });
+
+  it('normalise les erreurs serveur en RestError (code + status)', async () => {
+    const rest = new RestClient(
+      { baseUrl: 'http://127.0.0.1:7317', token: 'bad' },
+      fakeFetch({ ok: false, status: 401, body: { error: { code: 'BAD_TOKEN', message: 'invalid token' } } }, []),
+    );
+    await expect(rest.me()).rejects.toMatchObject({ code: 'BAD_TOKEN', status: 401 });
+    await expect(rest.me()).rejects.toBeInstanceOf(RestError);
+  });
+
+  it('encode les ids dans les chemins et envoie le corps JSON', async () => {
+    const captured: Captured[] = [];
+    const rest = new RestClient(
+      { baseUrl: 'http://h:1', token: 't' },
+      fakeFetch({ ok: true, status: 200, body: { worktree: {} } }, captured),
+    );
+    await rest.commitWorktree('repo id', { path: '/w', message: 'msg' });
+    expect(captured[0]?.url).toBe('http://h:1/api/v1/repos/repo%20id/worktrees/commit');
+    expect(captured[0]?.init.method).toBe('POST');
+    expect(JSON.parse(String(captured[0]?.init.body))).toEqual({ path: '/w', message: 'msg' });
+  });
+});