fix: comprehensive security, stability, and code quality audit

Security:
- Force API key auth for LAN (non-loopback) requests; remove shipped dev key
- Block path-traversal in backup restore; require auth on backup endpoints
- SSRF protection: DNS resolve + private/loopback/link-local IP rejection
- AES-256-GCM encryption for HA tokens and MQTT passwords with auto-migration
- WebSocket auth migrated from query-string to first-message protocol
- Asset upload: extension allowlist, server-side mime, Content-Disposition
- Update installer: SHA256 verification, tar/zip member validation
- Tightened CORS (explicit methods/headers, no credentials)
- ADB serial regex allowlist, webhook rate-limit key fix, log scrubbing

Android:
- Root-capture: ordered teardown, screenrecord respawn watchdog, child reaping
- USB permission blocking API via CompletableDeferred
- Python init crash guard with fatal-error screen
- Moved root grant + QR generation off Main thread
- Cached PyObject engine for per-frame bridge calls
- Ordered ScreenCapture resource cleanup, allowBackup=false

Python:
- Replaced all asyncio.get_event_loop() with get_running_loop/to_thread
- Split color_strip_sources.py (1683->5 files) and color_strip_stream.py
  (1324->7 files) into packages
- Extracted FrameLimiter utility, migrated 9 stream loops
- Provider base-class reuse, WLED state caching + URL normalization
- Narrowed broad except-pass in WS routes, threading fixes in BaseStore

Frontend:
- XSS fix: escapeHtml on dynamic option labels, reconcile-based list renders
- Typed DOM helpers, safe localStorage access, AbortController listener hygiene
- openAuthedWs helper for first-message WS auth protocol
- Migrated remaining plain <select>s to IconSelect/EntitySelect

Design:
- WCAG AA primary color on light theme (#2e7d32, 5.4:1 contrast)
- Android TV 10-foot breakpoint (tv.css)
- Consolidated z-index tokens, unified easing, card-running GPU hints

server/pyproject.toml

@@ -25,6 +25,7 @@ classifiers = [
 dependencies = [
     "fastapi>=0.115.0",
     "uvicorn[standard]>=0.32.0",
+    "cryptography>=42.0.0",
     "httpx>=0.27.2",
     "mss>=9.0.2",
     "numpy>=2.1.3",