security+robustness(py/gui): thread-safety, upload hardening, keyring

macro_manager:
- All macro reads/writes guarded by a lock; macros.json written atomically
  (temp + fsync + os.replace). Commands are copied under the lock and executed
  outside it so wait/keyboard steps don't block other threads.
- last_used disk writes debounced (>=5s) instead of a full rewrite per press.
- Validate key/hotkey names against pyautogui.KEYBOARD_KEYS and clamp wait ms;
  invalid input is skipped/logged, not blindly executed.

web_server:
- WebSocket receive loop always disconnects (fixes dead-socket leak); broadcast
  prunes failed sockets.
- POST /api/execute offloaded to a thread executor so a long macro no longer
  blocks the event loop.
- Image upload hardened: 5MB cap (413), real-image validation via Pillow,
  server-generated name under macro_images/, returns a relative path only,
  cleans up on failure.

gui:
- Execute macros off the Qt main thread (signal back to status bar); debounce
  resizeEvent and only rebuild when the column count changes.
- Relay password stored in the OS keyring when available (plaintext JSON blanked;
  graceful fallback if no backend); delete dialogs name the macro; honor the
  minimize-to-tray setting; surface save failures.
- Add media/system keys (volume, play/pause, track nav) to the macro editor.
- THEME gains shared danger/accent-hover colors; drop dead imports.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

config.py

@@ -13,7 +13,10 @@ THEME = {
     'button_bg': "#505050",
     'button_fg': "#ffffff",
     'tab_bg': "#404040",
-    'tab_selected': "#007acc"
+    'tab_selected': "#007acc",
+    'accent_hover': "#0096ff",
+    'danger_color': "#dc3545",
+    'danger_hover': "#c82333"
 }
 
 # File extensions for images