chore: remove vestigial sentinel flip code

- Remove deprecated _trigger_sentinel_async function and all call sites
- Clean up force_sentinel_reload option handling (replaced with Unity's synchronous system)
- Addresses repeated CodeRabbit flagging of unused vestigial code

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: dsarno

UnityMcpBridge/UnityMcpServer~/src/tools/manage_script_edits.py

@@ -193,37 +193,6 @@ def _find_best_closing_brace_match(matches, text: str):
     return best_match
 
 
-def _trigger_sentinel_async() -> None:
-    """Fire the Unity menu flip on a short-lived background thread.
-
-    This avoids blocking the current request or getting stuck during domain reloads
-    (socket reconnects) when the Editor recompiles.
-    """
-    try:
-        import threading, time
-
-        def _flip():
-            try:
-                import json, glob, os
-                # Small delay so write flushes; prefer early flip to avoid editor-focus second reload
-                time.sleep(0.1)
-                try:
-                    files = sorted(glob.glob(os.path.expanduser("~/.unity-mcp/unity-mcp-status-*.json")), key=os.path.getmtime, reverse=True)
-                    if files:
-                        with open(files[0], "r") as f:
-                            st = json.loads(f.read())
-                            if st.get("reloading"):
-                                return
-                except Exception:
-                    pass
-
-            except Exception:
-                pass
-
-        threading.Thread(target=_flip, daemon=True).start()
-    except Exception:
-        pass
-
 def _infer_class_name(script_name: str) -> str:
     # Default to script name as class name (common Unity pattern)
     return (script_name or "").strip()
@@ -578,12 +547,7 @@ def error_with_hint(message: str, expected: Dict[str, Any], suggestion: Dict[str
             }
             resp_struct = send_command_with_retry("manage_script", params_struct)
             if isinstance(resp_struct, dict) and resp_struct.get("success"):
-                # Optional: flip sentinel only if explicitly requested
-                if (options or {}).get("force_sentinel_reload"):
-                    try:
-                        _trigger_sentinel_async()
-                    except Exception:
-                        pass
+                pass  # Optional sentinel reload removed (deprecated)
             return _with_norm(resp_struct if isinstance(resp_struct, dict) else {"success": False, "message": str(resp_struct)}, normalized_for_echo, routing="structured")
 
         # 1) read from Unity
@@ -704,12 +668,7 @@ def _expand_dollars(rep: str) -> str:
                     resp_text = send_command_with_retry("manage_script", params_text)
                     if not (isinstance(resp_text, dict) and resp_text.get("success")):
                         return _with_norm(resp_text if isinstance(resp_text, dict) else {"success": False, "message": str(resp_text)}, normalized_for_echo, routing="mixed/text-first")
-                    # Successful text write; flip sentinel only if explicitly requested
-                    if (options or {}).get("force_sentinel_reload"):
-                        try:
-                            _trigger_sentinel_async()
-                        except Exception:
-                            pass
+                    # Optional sentinel reload removed (deprecated)
             except Exception as e:
                 return _with_norm({"success": False, "message": f"Text edit conversion failed: {e}"}, normalized_for_echo, routing="mixed/text-first")
 
@@ -728,11 +687,7 @@ def _expand_dollars(rep: str) -> str:
                 }
                 resp_struct = send_command_with_retry("manage_script", params_struct)
                 if isinstance(resp_struct, dict) and resp_struct.get("success"):
-                    if (options or {}).get("force_sentinel_reload"):
-                        try:
-                            _trigger_sentinel_async()
-                        except Exception:
-                            pass
+                    pass  # Optional sentinel reload removed (deprecated)
                 return _with_norm(resp_struct if isinstance(resp_struct, dict) else {"success": False, "message": str(resp_struct)}, normalized_for_echo, routing="mixed/text-first")
 
             return _with_norm({"success": True, "message": "Applied text edits (no structured ops)"}, normalized_for_echo, routing="mixed/text-first")
@@ -851,11 +806,7 @@ def _expand_dollars(rep: str) -> str:
                 }
                 resp = send_command_with_retry("manage_script", params)
                 if isinstance(resp, dict) and resp.get("success"):
-                    if (options or {}).get("force_sentinel_reload"):
-                        try:
-                            _trigger_sentinel_async()
-                        except Exception:
-                            pass
+                    pass  # Optional sentinel reload removed (deprecated)
                 return _with_norm(
                     resp if isinstance(resp, dict) else {"success": False, "message": str(resp)},
                     normalized_for_echo,
@@ -937,11 +888,7 @@ def _expand_dollars(rep: str) -> str:
 
         write_resp = send_command_with_retry("manage_script", params)
         if isinstance(write_resp, dict) and write_resp.get("success"):
-            if (options or {}).get("force_sentinel_reload"):
-                try:
-                    _trigger_sentinel_async()
-                except Exception:
-                    pass
+            pass  # Optional sentinel reload removed (deprecated)
         return _with_norm(
             write_resp if isinstance(write_resp, dict) 
                       else {"success": False, "message": str(write_resp)},