P2: découverte & reprise des sessions Claude

Arboretum découvre désormais toutes les sessions Claude de la machine
(scan ~/.claude/projects + registre ~/.claude/sessions), distingue
vivantes/mortes par pid+procStart, et permet de reprendre une morte
(--resume dans son cwd d'origine) ou forker une vivante sans la corrompre.

- shared: SessionSummary enrichi (source, claudeSessionId, pid, resumable,
  attachable, registryStatus) — additif, PROTOCOL_VERSION inchangé ;
  types REST resume/fork.
- db: migration id:2 (claude_session_id, resumed_from).
- core: jsonl-discovery (parseur tolérant, scan asynchrone non bloquant),
  session-registry (vivacité pid+procStart), discovery-service (cache +
  refresh périodique + diff/broadcast), pty-manager (resume/fork + capture
  du claudeSessionId via le registre).
- routes: /sessions/:id/resume (garde-fou 409 anti-corruption sur session
  vivante) et /fork ; GET fusionné managées + découvertes ; relais WS.
- web: badges managed/discovered + busy/idle/waiting, actions conditionnelles
  (Open/Observe/Kill vs Fork/View vs Resume/Fork), vue read-only des sessions
  externes, i18n EN/FR.
- tests: jsonl-discovery, session-registry, discovery-service + resume/fork
  (130 verts) ; acceptation E2E acceptance-p2.mjs (sans quota) ALL GREEN.

Conforme aux verdicts S1 (resume dans cwd d'origine, vivacité pid+procStart)
et S4 (munge cwd, parseur tête+queue, priorité de titre).

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

packages/server/test/pty-manager.test.ts

@@ -1,9 +1,14 @@
 import { tmpdir } from 'node:os';
+import { mkdtempSync, writeFileSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
 import { beforeEach, describe, expect, it, vi, type Mock } from 'vitest';
 import { FLOW, REPLAY_TAIL_BYTES, type SessionSummary } from '@arboretum/shared';
 import { PtyManager, type ClientBinding } from '../src/core/pty-manager.js';
 import { openDb, type Db } from '../src/db/index.js';
 
+// resolveClaudeBin() fait `which claude` : on le stub pour ne pas dépendre d'un claude réel en PATH.
+vi.mock('node:child_process', () => ({ execFileSync: () => '/usr/bin/claude\n' }));
+
 interface FakePty {
   pid: number;
   file: string;
@@ -135,6 +140,68 @@ describe('PtyManager (pty mocké)', () => {
       const row = db.prepare('SELECT COUNT(*) AS n FROM sessions').get() as { n: number };
       expect(row.n).toBe(0);
     });
+
+    it('summarize expose les champs P2 (source/attachable/resumable/pid)', () => {
+      const { summary } = spawnBash();
+      expect(summary).toMatchObject({
+        source: 'managed',
+        attachable: true,
+        resumable: false,
+        registryStatus: null,
+        claudeSessionId: null,
+      });
+      expect(summary.pid).toBeGreaterThan(0);
+    });
+  });
+
+  describe('resume / fork (P2)', () => {
+    it('resume → pty claude avec --resume, command forcé à claude, resumed_from persisté', () => {
+      const summary = manager.spawn({ cwd, resume: { claudeSessionId: 'abc-123' } });
+      const p = lastPty();
+      expect(summary.command).toBe('claude');
+      expect(summary.source).toBe('managed');
+      expect(summary.attachable).toBe(true);
+      expect(p.file).toBe('/usr/bin/claude');
+      expect(p.args).toEqual(['--resume', 'abc-123']);
+      const row = db.prepare('SELECT resumed_from, command FROM sessions WHERE id = ?').get(summary.id) as {
+        resumed_from: string | null;
+        command: string;
+      };
+      expect(row).toEqual({ resumed_from: 'abc-123', command: 'claude' });
+    });
+
+    it('fork → --resume <id> --fork-session', () => {
+      manager.spawn({ cwd, resume: { claudeSessionId: 'xyz', fork: true } });
+      expect(lastPty().args).toEqual(['--resume', 'xyz', '--fork-session']);
+    });
+
+    it('session claude morte avec claudeSessionId connu → resumable dans list()', () => {
+      const summary = manager.spawn({ cwd, resume: { claudeSessionId: 'sid-known' } });
+      // simule la capture du claudeSessionId (normalement résolue via le registre)
+      db.prepare('UPDATE sessions SET claude_session_id = ? WHERE id = ?').run('sid-known', summary.id);
+      lastPty().emitExit(0);
+      const listed = manager.list().find((s) => s.id === summary.id);
+      expect(listed).toMatchObject({ live: false, resumable: true, claudeSessionId: 'sid-known' });
+    });
+
+    it('capture le claudeSessionId via le registre (poll par pid) → findLiveByClaudeSessionId', () => {
+      vi.useFakeTimers();
+      const sessDir = mkdtempSync(join(tmpdir(), 'arb-sess-'));
+      try {
+        const m = new PtyManager(db, sessDir);
+        const summary = m.spawn({ cwd, command: 'claude' });
+        const p = lastPty();
+        writeFileSync(join(sessDir, `${p.pid}.json`), JSON.stringify({ pid: p.pid, sessionId: 'captured-sid', status: 'idle' }));
+        expect(m.findLiveByClaudeSessionId('captured-sid')).toBeNull(); // pas encore capturé
+        vi.advanceTimersByTime(400);
+        const found = m.findLiveByClaudeSessionId('captured-sid');
+        expect(found?.id).toBe(summary.id);
+        expect(found?.claudeSessionId).toBe('captured-sid');
+      } finally {
+        vi.useRealTimers();
+        rmSync(sessDir, { recursive: true, force: true });
+      }
+    });
   });
 
   describe('attach', () => {