Comprehensive review fixes: security, performance, code quality, and UI polish

Backend: Fix CORS wildcard+credentials, add secret key warning, remove raw
API keys from sync endpoint, fix N+1 queries in watcher/sync, fix
AttributeError on event_types, delete dead scheduled.py/templates.py,
add limit cap on history, re-validate server on URL/key update, apply
tracking/template config IDs in update_target.

HA Integration: Replace datetime.now() with dt_util.now(), fix notification
queue to only remove successfully sent items, use album UUID for entity
unique IDs, add shared links dirty flag and users cache hourly refresh,
deduplicate _is_quiet_hours, add HTTP timeouts, cache albums in config
flow, change iot_class to local_polling.

Frontend: Make i18n reactive via $state (remove window.location.reload),
add Modal transitions/a11y/Escape key, create ConfirmModal replacing all
confirm() calls, add error handling to all pages, replace Unicode nav
icons with MDI SVGs, add card hover effects, dashboard stat icons, global
focus-visible styles, form slide transitions, mobile responsive bottom
nav, fix password error color, add ~20 i18n keys (EN/RU).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

custom_components/immich_album_watcher/manifest.json

@@ -5,7 +5,7 @@
     "config_flow": true,
     "dependencies": [],
     "documentation": "https://github.com/DolgolyovAlexei/haos-hacs-immich-album-watcher",
-    "iot_class": "cloud_polling",
+    "iot_class": "local_polling",
     "issue_tracker": "https://github.com/DolgolyovAlexei/haos-hacs-immich-album-watcher/issues",
     "requirements": ["immich-watcher-core==0.1.0"],
     "version": "2.8.0"