feat: grouped nav tree with badges, dashboard events section with filtered chart

Navigation:
- Restructure flat nav into grouped tree: Notification (Trackers,
  Configs, Templates), Commands (same), Bots (Telegram), Settings
  (Common, Users)
- Collapsible groups with expand/collapse state persisted in localStorage
- Auto-expand group containing the active page
- Counter badges on groups (sum of children) and individual items
- New /api/status/counts endpoint for nav badge data
- Mobile bottom nav uses flattened key pages

Dashboard:
- Rename "Recent Events" to "Events"
- Move chart under Events section (after filters, before event list)
- Filters (event type, provider, search) now affect both the event
  list AND the chart simultaneously
- Add event_type, provider_id, search filter params to /api/status/chart

frontend/src/lib/i18n/en.json

@@ -16,7 +16,17 @@
 		"cmdTemplateConfigs": "Cmd Templates",
 		"users": "Users",
 		"settings": "Settings",
-		"logout": "Logout"
+		"logout": "Logout",
+		"notification": "Notification",
+		"commands": "Commands",
+		"bots": "Bots",
+		"trackers": "Trackers",
+		"configs": "Configs",
+		"templates": "Templates",
+		"telegram": "Telegram",
+		"email": "Email",
+		"matrix": "Matrix",
+		"common": "Common"
 	},
 	"auth": {
 		"signIn": "Sign in",
@@ -39,7 +49,7 @@
 		"providers": "Providers",
 		"activeTrackers": "Active Trackers",
 		"targets": "Targets",
-		"recentEvents": "Recent Events",
+		"recentEvents": "Events",
 		"noEvents": "No events yet. Create a tracker to start monitoring.",
 		"loading": "Loading...",
 		"justNow": "just now",
@@ -253,7 +263,7 @@
 		"enabledCommands": "Enabled commands",
 		"defaultCount": "Default count",
 		"responseMode": "Response mode",
-		"modeMedia": "Media (photos)",
+		"modeMedia": "Media (files)",
 		"modeText": "Text only",
 		"botLocale": "Bot language",
 		"rateLimits": "Rate Limits",
@@ -396,13 +406,27 @@
 		"invalidFormat": "Invalid format string"
 	},
 	"templateVars": {
-		"message_assets_added": { "description": "Notification when new assets are added to an album" },
-		"message_assets_removed": { "description": "Notification when assets are removed from an album" },
-		"message_album_renamed": { "description": "Notification when an album is renamed" },
-		"message_album_deleted": { "description": "Notification when an album is deleted" },
-		"periodic_summary_message": { "description": "Periodic album summary (scheduler not yet implemented)" },
-		"scheduled_assets_message": { "description": "Scheduled asset delivery (scheduler not yet implemented)" },
-		"memory_mode_message": { "description": "\"On This Day\" memories (scheduler not yet implemented)" },
+		"message_assets_added": {
+			"description": "Notification when new assets are added to an album"
+		},
+		"message_assets_removed": {
+			"description": "Notification when assets are removed from an album"
+		},
+		"message_album_renamed": {
+			"description": "Notification when an album is renamed"
+		},
+		"message_album_deleted": {
+			"description": "Notification when an album is deleted"
+		},
+		"periodic_summary_message": {
+			"description": "Periodic album summary (scheduler not yet implemented)"
+		},
+		"scheduled_assets_message": {
+			"description": "Scheduled asset delivery (scheduler not yet implemented)"
+		},
+		"memory_mode_message": {
+			"description": "\"On This Day\" memories (scheduler not yet implemented)"
+		},
 		"album_id": "Album ID (UUID)",
 		"album_name": "Album name",
 		"album_url": "Public share URL (empty if not shared)",
@@ -544,7 +568,7 @@
 		"enabledCommands": "Enabled Commands",
 		"locale": "Locale",
 		"responseMode": "Response Mode",
-		"modeMedia": "Media (photos)",
+		"modeMedia": "Media (files)",
 		"modeText": "Text only",
 		"defaultCount": "Default Count",
 		"rateLimits": "Rate Limits",
@@ -662,4 +686,4 @@
 		"line": "line",
 		"add": "Add"
 	}
-}
+}