perf: reduce portable build size ~40MB — replace winsdk/wmi, migrate cv2 to Pillow

- Replace winsdk (~35MB) with winrt packages (~2.5MB) for OS notification
  listener. API is identical, 93% size reduction.
- Replace wmi (~3-5MB) with ctypes for monitor names (EnumDisplayDevicesW)
  and camera names (SetupAPI). Zero external dependency.
- Migrate cv2.resize/imencode/LUT to Pillow/numpy in 5 files (filters,
  preview helpers, kc_target_processor). OpenCV only needed for camera
  and video stream now.
- Fix DefWindowProcW ctypes overflow on 64-bit Python (pre-existing bug
  in platform_detector display power listener).
- Fix openLightbox import in streams-capture-templates.ts (was using
  broken window cast instead of direct import).
- Add mandatory data migration policy to CLAUDE.md after silent data
  loss incident from storage file rename without migration.

server/src/wled_controller/utils/monitor_names.py

@@ -1,5 +1,6 @@
 """Utility functions for retrieving friendly monitor/display names."""
 
+import ctypes
 import sys
 from typing import Dict
 
@@ -11,7 +12,8 @@ logger = get_logger(__name__)
 def get_monitor_names() -> Dict[int, str]:
     """Get friendly names for connected monitors.
 
-    On Windows, attempts to retrieve monitor names from WMI.
+    On Windows, enumerates display adapters and their monitors via
+    ``EnumDisplayDevicesW`` (pure ctypes, no third-party dependencies).
     On other platforms, returns empty dict (will fall back to generic names).
 
     Returns:
@@ -22,47 +24,68 @@ def get_monitor_names() -> Dict[int, str]:
         return {}
 
     try:
-        import wmi
+        from ctypes import wintypes
 
-        w = wmi.WMI(namespace="wmi")
-        monitors = w.WmiMonitorID()
+        class DISPLAY_DEVICEW(ctypes.Structure):
+            _fields_ = [
+                ("cb", wintypes.DWORD),
+                ("DeviceName", ctypes.c_wchar * 32),
+                ("DeviceString", ctypes.c_wchar * 128),
+                ("StateFlags", wintypes.DWORD),
+                ("DeviceID", ctypes.c_wchar * 128),
+                ("DeviceKey", ctypes.c_wchar * 128),
+            ]
 
-        monitor_names = {}
+        user32 = ctypes.windll.user32
 
-        for idx, monitor in enumerate(monitors):
-            try:
-                # Extract manufacturer name
-                manufacturer = ""
-                if monitor.ManufacturerName:
-                    manufacturer = "".join(chr(c) for c in monitor.ManufacturerName if c != 0)
+        DISPLAY_DEVICE_ACTIVE = 0x00000001
+        DISPLAY_DEVICE_ATTACHED_TO_DESKTOP = 0x00000002
 
-                # Extract user-friendly name
-                user_name = ""
-                if monitor.UserFriendlyName:
-                    user_name = "".join(chr(c) for c in monitor.UserFriendlyName if c != 0)
+        monitor_names: Dict[int, str] = {}
+        monitor_idx = 0
 
-                # Build friendly name
-                if user_name:
-                    friendly_name = user_name.strip()
-                elif manufacturer:
-                    friendly_name = f"{manufacturer.strip()} Monitor"
-                else:
-                    friendly_name = f"Display {idx}"
+        # Enumerate display adapters (GPUs / virtual outputs)
+        adapter_idx = 0
+        while adapter_idx < 16:  # safety limit
+            adapter = DISPLAY_DEVICEW()
+            adapter.cb = ctypes.sizeof(DISPLAY_DEVICEW)
 
-                monitor_names[idx] = friendly_name
-                logger.debug(f"Monitor {idx}: {friendly_name}")
+            if not user32.EnumDisplayDevicesW(None, adapter_idx, ctypes.byref(adapter), 0):
+                break
+            adapter_idx += 1
 
-            except Exception as e:
-                logger.debug(f"Failed to parse monitor {idx} name: {e}")
-                monitor_names[idx] = f"Display {idx}"
+            # Skip adapters not attached to the desktop
+            if not (adapter.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP):
+                continue
+
+            # Enumerate monitors attached to this adapter
+            child_idx = 0
+            while child_idx < 16:  # safety limit
+                monitor = DISPLAY_DEVICEW()
+                monitor.cb = ctypes.sizeof(DISPLAY_DEVICEW)
+
+                if not user32.EnumDisplayDevicesW(
+                    adapter.DeviceName, child_idx, ctypes.byref(monitor), 0
+                ):
+                    break
+                child_idx += 1
+
+                if not (monitor.StateFlags & DISPLAY_DEVICE_ACTIVE):
+                    continue
+
+                # DeviceString contains the friendly name (e.g. "DELL U2718Q")
+                friendly_name = monitor.DeviceString.strip()
+                if not friendly_name:
+                    friendly_name = f"Display {monitor_idx}"
+
+                monitor_names[monitor_idx] = friendly_name
+                logger.debug(f"Monitor {monitor_idx}: {friendly_name}")
+                monitor_idx += 1
 
         return monitor_names
 
-    except ImportError:
-        logger.debug("WMI library not available - install with: pip install wmi")
-        return {}
     except Exception as e:
-        logger.debug(f"Failed to retrieve monitor names via WMI: {e}")
+        logger.debug(f"Failed to retrieve monitor names via EnumDisplayDevices: {e}")
         return {}