snapshot: WIP 5j replay reliability (B1 watchdog + dialog handlers + grounding drift)

Snapshot avant correction du blocage relance Léa (3 incidents 24h: SSH refusé,
polls morts ×2). Point de rollback stable.

Contenu:
- agent_v1/core/executor.py: 5 patchs dialog handling (saveas drift, close_tab
  hotkey fallback, confirm_save Unicode apostrophe, foreground dialog
  recontextualization, runtime_dialog in-loop) + helpers normalize_window_hint,
  requires_post_verify_window_transition
- agent_v1/core/grounding.py: garde drift template fix (fallback_x/y plumbed)
- server_v1/replay_watchdog.py (NEW): orphan watchdog B1, scan 10s timeout 30s
- server_v1/api_stream.py: dispatched_action plumbing, watchdog lifespan,
  metrics endpoint
- server_v1/replay_engine.py: _schedule_retry préserve original_action +
  dispatched_action
- stream_processor.py: gardes _infer_tab_switch_target (no false switch_tab
  on save_as dialog open) + _attach_expected_window_before
- tests/integration: test_replay_watchdog.py (8 cas), test_stream_processor.py
- tests/unit: test_executor_verify_window_guard.py (start_button, close_tab,
  runtime_dialog, post_verify, transition fallbacks)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

agent_v0/server_v1/live_session_manager.py

@@ -17,6 +17,20 @@ from typing import Any, Dict, List, Optional
 logger = logging.getLogger(__name__)
 
 
+def _infer_machine_id_from_session_id(session_id: str, fallback: str = "default") -> str:
+    """Déduire le machine_id depuis un session_id spécial si possible.
+
+    Les heartbeats de fond de Léa utilisent `bg_<machine_id>` comme
+    identifiant de session. Lors d'un redémarrage serveur, ces sessions
+    peuvent être restaurées depuis la persistance JSON avec `machine_id`
+    resté à `default`. On rétablit ici l'information machine pour que les
+    replays ciblés retrouvent bien la session de fond active.
+    """
+    if session_id.startswith("bg_") and len(session_id) > 3:
+        return session_id[3:]
+    return fallback
+
+
 @dataclass
 class LiveSessionState:
     """État d'une session active en mémoire."""
@@ -86,11 +100,18 @@ class LiveSessionManager:
     def _load_persisted_sessions(self):
         """Charger les sessions sauvegardées au démarrage (JSON state files)."""
         count = 0
-        for session_file in sorted(self._persist_dir.glob("sess_*.json")):
+        session_files = sorted(self._persist_dir.glob("sess_*.json"))
+        session_files += sorted(self._persist_dir.glob("bg_*.json"))
+        for session_file in session_files:
             try:
                 with open(session_file, 'r', encoding='utf-8') as f:
                     data = json.load(f)
                 session = LiveSessionState.from_dict(data)
+                if session.machine_id == "default":
+                    session.machine_id = _infer_machine_id_from_session_id(
+                        session.session_id,
+                        fallback=session.machine_id,
+                    )
                 self._sessions[session.session_id] = session
                 count += 1
             except Exception as e:
@@ -117,7 +138,7 @@ class LiveSessionManager:
         for jsonl_file in sorted(live_dir.glob("**/live_events.jsonl")):
             session_dir = jsonl_file.parent
             session_id = session_dir.name
-            if not session_id.startswith("sess_"):
+            if not (session_id.startswith("sess_") or session_id.startswith("bg_")):
                 continue
             if session_id in self._sessions:
                 continue
@@ -125,7 +146,7 @@ class LiveSessionManager:
             # Déduire le machine_id depuis le chemin parent
             parent_name = session_dir.parent.name
             if parent_name == live_dir.name:
-                machine_id = "default"
+                machine_id = _infer_machine_id_from_session_id(session_id)
             else:
                 machine_id = parent_name