feat(qw2): hook LoopDetector dans api_stream + extension replay_state

replay_state enrichi de _screenshot_history (5 dernières images PIL) et
_action_history (5 dernières signatures action).

report_action_result :
- met à jour les deux anneaux après chaque action
- évalue le LoopDetector (singleton lazy avec _clip_embedder serveur)
- si detected → bascule paused_need_help avec pause_reason="loop_detected"
  et bus event lea:loop_detected (signal + evidence)

Tous les chemins d'erreur (embedder absent, OOM, exception) loggent et
laissent le replay continuer — aucun blocage par la couche détection.

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

tests/integration/test_loop_detector_replay.py

@@ -0,0 +1,61 @@
+# tests/integration/test_loop_detector_replay.py
+"""Tests intégration : un replay simulé qui boucle bascule en paused_need_help."""
+import pytest
+from unittest.mock import MagicMock
+
+from agent_v0.server_v1.loop_detector import LoopDetector
+
+
+def test_replay_state_transitions_to_paused_on_screen_static():
+    """Cas : 4 screenshots identiques → replay passe à paused_need_help."""
+    embedder = MagicMock()
+    embedder.embed_image.return_value = [1.0, 0.0, 0.0]  # constant
+    detector = LoopDetector(clip_embedder=embedder)
+
+    state = {
+        "replay_id": "r_test",
+        "status": "running",
+        "retried_actions": 0,
+        "_screenshot_history": ["img1", "img2", "img3", "img4"],  # 4 images factices
+        "_action_history": [
+            {"type": "click", "x_pct": 0.1, "y_pct": 0.1},
+            {"type": "type", "x_pct": 0.2, "y_pct": 0.2},
+        ],
+    }
+    verdict = detector.evaluate(state, state["_screenshot_history"], state["_action_history"])
+
+    # Simuler ce que ferait api_stream après verdict
+    if verdict.detected:
+        state["status"] = "paused_need_help"
+        state["pause_reason"] = verdict.reason
+        state["pause_message"] = f"signal={verdict.signal}"
+
+    assert state["status"] == "paused_need_help"
+    assert state["pause_reason"] == "loop_detected"
+    assert "screen_static" in state["pause_message"]
+
+
+def test_replay_state_transitions_on_action_repeat():
+    """Cas : 3 actions identiques → paused_need_help signal action_repeat."""
+    detector = LoopDetector(clip_embedder=None)
+    actions = [{"type": "click", "x_pct": 0.5, "y_pct": 0.5}] * 3
+    state = {"replay_id": "r2", "status": "running", "retried_actions": 0,
+             "_screenshot_history": [], "_action_history": actions}
+
+    verdict = detector.evaluate(state, [], actions)
+    assert verdict.detected and verdict.signal == "action_repeat"
+
+
+def test_kill_switch_keeps_replay_running(monkeypatch):
+    """Avec RPA_LOOP_DETECTOR_ENABLED=0 le replay continue même en boucle."""
+    monkeypatch.setenv("RPA_LOOP_DETECTOR_ENABLED", "0")
+    embedder = MagicMock()
+    embedder.embed_image.return_value = [1.0, 0.0, 0.0]
+    detector = LoopDetector(clip_embedder=embedder)
+
+    state = {"retried_actions": 10,
+             "_screenshot_history": ["img1"] * 10,
+             "_action_history": [{"type": "click", "x_pct": 0.5, "y_pct": 0.5}] * 10}
+
+    verdict = detector.evaluate(state, state["_screenshot_history"], state["_action_history"])
+    assert verdict.detected is False