feat(qw4): SafetyChecksProvider hybride déclaratif + LLM contextuel

build_pause_payload(action, state, last_screenshot) → PausePayload
- Toujours inclure les checks déclaratifs (workflow.parameters.safety_checks)
- Si safety_level=medical_critical ET RPA_SAFETY_CHECKS_LLM_ENABLED=1 :
    appel LLM (medgemma:4b par défaut) en format=json strict, timeout 5s,
    max 3 checks ajoutés (configurables via env vars)
- Tous les chemins d'erreur (timeout, HTTP, JSON parse, exception) loggent
  et retournent [] (fallback safe : déclaratifs seuls)

Tests : 7 cas (déclaratif seul, hybride OK, timeout, LLM invalide,
kill-switch, max_checks, déclaratif vide).

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

agent_v0/server_v1/safety_checks_provider.py

@@ -0,0 +1,191 @@
+# agent_v0/server_v1/safety_checks_provider.py
+"""SafetyChecksProvider — checks hybrides déclaratifs + LLM contextuels (QW4).
+
+Pour une action pause_for_human :
+- les checks déclaratifs (workflow) sont toujours inclus
+- si safety_level == "medical_critical" et RPA_SAFETY_CHECKS_LLM_ENABLED=1,
+  un appel LLM (medgemma:4b par défaut) ajoute jusqu'à N checks contextuels
+
+Tout échec côté LLM (timeout, exception, parse) → additional_checks=[] :
+le replay continue avec uniquement les déclaratifs (fallback safe).
+"""
+
+import base64
+import io
+import json
+import logging
+import os
+import uuid
+from dataclasses import dataclass, field
+from typing import Any, Dict, List, Optional
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class PausePayload:
+    checks: List[Dict[str, Any]] = field(default_factory=list)
+    pause_reason: str = ""
+    message: str = ""
+
+
+def _env(name: str, default: str) -> str:
+    return os.environ.get(name, default).strip()
+
+
+def _env_int(name: str, default: int) -> int:
+    try:
+        return int(os.environ.get(name, default))
+    except (TypeError, ValueError):
+        return default
+
+
+def _env_bool_enabled(name: str) -> bool:
+    val = os.environ.get(name, "1").strip().lower()
+    return val not in ("0", "false", "no", "off", "")
+
+
+def build_pause_payload(
+    action: Dict[str, Any],
+    replay_state: Dict[str, Any],
+    last_screenshot: Optional[str],
+) -> PausePayload:
+    """Construit le payload de pause enrichi pour une action pause_for_human."""
+    params = action.get("parameters") or {}
+    message = params.get("message", "Validation requise")
+    safety_level = params.get("safety_level")
+    declarative = params.get("safety_checks") or []
+
+    # Normalisation des checks déclaratifs
+    checks: List[Dict[str, Any]] = []
+    for d in declarative:
+        checks.append({
+            "id": d.get("id") or f"decl_{uuid.uuid4().hex[:6]}",
+            "label": d.get("label", "Validation"),
+            "required": bool(d.get("required", True)),
+            "source": "declarative",
+            "evidence": None,
+        })
+
+    # Ajout LLM contextual si applicable
+    if safety_level == "medical_critical" and _env_bool_enabled("RPA_SAFETY_CHECKS_LLM_ENABLED"):
+        try:
+            additional = _call_llm_for_contextual_checks(
+                action=action,
+                replay_state=replay_state,
+                last_screenshot=last_screenshot,
+                existing_labels=[c["label"] for c in checks],
+            )
+        except Exception as e:
+            logger.warning("safety_checks LLM exception (%s) — fallback safe", e)
+            additional = []
+
+        for a in additional:
+            checks.append({
+                "id": f"llm_{uuid.uuid4().hex[:6]}",
+                "label": a.get("label", ""),
+                "required": False,  # checks LLM = informationnels, pas obligatoires V1
+                "source": "llm_contextual",
+                "evidence": a.get("evidence", ""),
+            })
+
+    return PausePayload(
+        checks=checks,
+        pause_reason="",
+        message=message,
+    )
+
+
+def _call_llm_for_contextual_checks(
+    action: Dict[str, Any],
+    replay_state: Dict[str, Any],
+    last_screenshot: Optional[str],
+    existing_labels: List[str],
+) -> List[Dict[str, str]]:
+    """Appelle Ollama en mode JSON strict pour générer 0-N checks contextuels.
+
+    Returns:
+        List[{label, evidence}] (max RPA_SAFETY_CHECKS_LLM_MAX_CHECKS).
+        [] sur tout échec (timeout, JSON invalide, exception).
+    """
+    import requests
+
+    model = _env("RPA_SAFETY_CHECKS_LLM_MODEL", "medgemma:4b")
+    timeout_s = _env_int("RPA_SAFETY_CHECKS_LLM_TIMEOUT_S", 5)
+    max_checks = _env_int("RPA_SAFETY_CHECKS_LLM_MAX_CHECKS", 3)
+    ollama_url = _env("OLLAMA_URL", "http://localhost:11434")
+
+    params = action.get("parameters") or {}
+    workflow_message = params.get("message", "")
+    existing = ", ".join(existing_labels) if existing_labels else "aucun"
+
+    prompt = f"""Tu es Léa, assistante médicale supervisée.
+Avant de continuer le workflow, tu dois lister 0 à {max_checks} vérifications supplémentaires
+que l'humain doit acquitter, en regardant l'écran actuel.
+
+Contexte workflow : {workflow_message}
+Checks déjà demandés : {existing}
+
+NE répète PAS un check déjà demandé.
+Si rien d'inhabituel à signaler, retourne {{"additional_checks": []}}.
+
+Réponds UNIQUEMENT en JSON :
+{{
+  "additional_checks": [
+    {{"label": "string court", "evidence": "ce que tu as vu d'inhabituel"}}
+  ]
+}}
+"""
+
+    payload = {
+        "model": model,
+        "prompt": prompt,
+        "stream": False,
+        "format": "json",
+        "options": {"temperature": 0.1, "num_predict": 200},
+    }
+
+    if last_screenshot and os.path.isfile(last_screenshot):
+        try:
+            with open(last_screenshot, "rb") as f:
+                payload["images"] = [base64.b64encode(f.read()).decode("ascii")]
+        except Exception as e:
+            logger.debug("safety_checks: lecture screenshot échouée (%s) — appel sans image", e)
+
+    try:
+        response = requests.post(
+            f"{ollama_url}/api/generate",
+            json=payload,
+            timeout=timeout_s,
+        )
+        if response.status_code != 200:
+            logger.warning("safety_checks LLM HTTP %s", response.status_code)
+            return []
+        text = response.json().get("response", "").strip()
+    except requests.Timeout:
+        logger.warning("safety_checks LLM timeout (%ss)", timeout_s)
+        return []
+    except Exception as e:
+        logger.warning("safety_checks LLM erreur réseau: %s", e)
+        return []
+
+    # format=json garantit normalement du JSON valide
+    try:
+        parsed = json.loads(text)
+    except json.JSONDecodeError as e:
+        logger.warning("safety_checks LLM JSON invalide (%s) — fallback safe", e)
+        return []
+
+    additional = parsed.get("additional_checks") or []
+    if not isinstance(additional, list):
+        return []
+
+    # Filtre + tronc
+    valid = []
+    for item in additional[:max_checks]:
+        if isinstance(item, dict) and item.get("label"):
+            valid.append({
+                "label": str(item["label"])[:200],
+                "evidence": str(item.get("evidence", ""))[:300],
+            })
+    return valid