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>

tests/unit/test_replay_critic.py

@@ -145,6 +145,20 @@ class TestVerifyWithCritic:
         assert result.suggestion == "retry"
         assert result.semantic_verified is None  # VLM non appelé
 
+    def test_verify_screen_identique_ne_declenche_pas_retry(
+        self, verifier, screenshot_gray,
+    ):
+        """verify_screen est une stabilisation, pas une action qui doit re-changer l'écran."""
+        result = verifier.verify_action(
+            action={"type": "verify_screen", "action_id": "verify_setup"},
+            result={"success": True},
+            screenshot_before=screenshot_gray,
+            screenshot_after=screenshot_gray,
+        )
+        assert result.verified is True
+        assert result.suggestion == "continue"
+        assert result.changes_detected is False
+
     @patch("agent_v0.server_v1.replay_verifier.ReplayVerifier._verify_semantic")
     def test_pixel_ok_semantic_ok(
         self, mock_semantic, verifier, screenshot_gray, screenshot_white,