fix(hermes-auto-improve): squash merge + correction PR existante dans create_github_pr

- GitHub repo configuré squash-only (allow_merge_commit=false, allow_rebase_merge=false)
- create_github_pr() vérifie si une PR hermes/daily-work est déjà ouverte :
  si oui → met à jour titre+body (pas de PR dupliquée)
  si non → crée une nouvelle PR
- Supprime le bug de silence sur "a pull request for branch X already exists"

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/hermes-auto-improve/trigger-server.py

@@ -31,6 +31,25 @@ _running     = False
 _last_result = None
 
 
+def _extract_last_json(text: str):
+    """Find the outermost JSON object at the end of mixed text+JSON output."""
+    end = text.rfind("}")
+    if end < 0:
+        return None
+    depth = 0
+    for i in range(end, -1, -1):
+        if text[i] == "}":
+            depth += 1
+        elif text[i] == "{":
+            depth -= 1
+            if depth == 0:
+                try:
+                    return json.loads(text[i:end + 1])
+                except json.JSONDecodeError:
+                    return None
+    return None
+
+
 def run_script(extra_args: list = None):
     global _running, _last_result
     with _lock:
@@ -50,13 +69,8 @@ def run_script(extra_args: list = None):
             if result.stderr:
                 log.write(f"STDERR: {result.stderr}")
 
-        out   = result.stdout
-        start = out.rfind("{")
-        end   = out.rfind("}") + 1
-        if start >= 0 and end > start:
-            _last_result = json.loads(out[start:end])
-        else:
-            _last_result = {"error": "no_json", "stdout": out[-500:]}
+        out = result.stdout
+        _last_result = _extract_last_json(out) or {"error": "no_json", "stdout": out[-500:]}
 
     except subprocess.TimeoutExpired:
         _last_result = {"error": "timeout"}