feat: add auto-update system with release checking, notification UI, and install-type-aware apply

- Abstract ReleaseProvider interface (Gitea impl, swappable for GitHub/GitLab)
- Background UpdateService with periodic checks, debounce, dismissed version persistence
- Install type detection (installer/portable/docker/dev) with platform-aware asset matching
- Download with progress events, silent NSIS reinstall, portable ZIP/tarball swap scripts
- Version badge pulse animation, dismissible banner with icon buttons, Settings > Updates tab
- Single source of truth: pyproject.toml version via importlib.metadata, CI stamps tag with sed
- API: GET/POST status, check, dismiss, apply, GET/PUT settings
- i18n: en, ru, zh (27+ keys each)

server/src/wled_controller/__init__.py

@@ -1,5 +1,12 @@
 """LED Grab - Ambient lighting based on screen content."""
 
-__version__ = "0.1.0"
+from importlib.metadata import version, PackageNotFoundError
+
+try:
+    __version__ = version("wled-screen-controller")
+except PackageNotFoundError:
+    # Running from source without pip install (e.g. dev, embedded Python)
+    __version__ = "0.0.0-dev"
+
 __author__ = "Alexei Dolgolyov"
 __email__ = "dolgolyov.alexei@gmail.com"