feat: entity relationship refactor — notification trackers, command system, chat actions

Rework entity schema: rename Tracker→NotificationTracker, add CommandConfig/
CommandTracker/CommandTrackerListener entities for decoupled command handling.
Commands now resolve through CommandTracker→CommandConfig instead of
TelegramBot.commands_config. Smart ref-counted bot polling based on active
listeners. Add chat_action to telegram targets. Full frontend CRUD pages
for command configs and command trackers. Idempotent SQLite migrations.

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

frontend/src/routes/+layout.svelte

@@ -39,11 +39,13 @@
 	const baseNavItems = [
 		{ href: '/', key: 'nav.dashboard', icon: 'mdiViewDashboard' },
 		{ href: '/providers', key: 'nav.providers', icon: 'mdiServer' },
-		{ href: '/trackers', key: 'nav.trackers', icon: 'mdiRadar' },
+		{ href: '/notification-trackers', key: 'nav.notificationTrackers', icon: 'mdiRadar' },
 		{ href: '/tracking-configs', key: 'nav.trackingConfigs', icon: 'mdiCog' },
 		{ href: '/template-configs', key: 'nav.templateConfigs', icon: 'mdiFileDocumentEdit' },
 		{ href: '/telegram-bots', key: 'nav.telegramBots', icon: 'mdiRobot' },
 		{ href: '/targets', key: 'nav.targets', icon: 'mdiTarget' },
+		{ href: '/command-trackers', key: 'nav.commandTrackers', icon: 'mdiConsoleLine' },
+		{ href: '/command-configs', key: 'nav.commandConfigs', icon: 'mdiCog' },
 	];
 	const navItems = $derived(auth.isAdmin
 		? [...baseNavItems, { href: '/users', key: 'nav.users', icon: 'mdiAccountGroup' }, { href: '/settings', key: 'nav.settings', icon: 'mdiCogOutline' }]