Phase 9: Telegram bot management with chat discovery

New entity + API:
- TelegramBot model (name, token, bot_username, bot_id)
- CRUD at /api/telegram-bots with token validation via getMe
- GET /{id}/chats: discover active chats via getUpdates
- GET /{id}/token: retrieve full token (for target config)

Frontend:
- /telegram-bots page: register bots, view discovered chats
  per bot (expandable), refresh on demand
- Targets page: select from registered bots (dropdown) instead
  of raw token input. Chat selector shows discovered chats
  when bot is selected, falls back to manual input.
  Bot token resolved server-side on save.

Nav icon uses monochrome symbol for consistency.

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

frontend/src/lib/i18n/en.json

@@ -9,6 +9,7 @@
 		"trackers": "Trackers",
 		"trackingConfigs": "Tracking",
 		"templateConfigs": "Templates",
+		"telegramBots": "Bots",
 		"targets": "Targets",
 		"users": "Users",
 		"logout": "Logout"
@@ -159,6 +160,25 @@
 		"confirmDelete": "Delete this user?",
 		"joined": "joined"
 	},
+	"telegramBot": {
+		"title": "Telegram Bots",
+		"description": "Register and manage Telegram bots",
+		"addBot": "Add Bot",
+		"name": "Display name",
+		"namePlaceholder": "Family notifications bot",
+		"token": "Bot Token",
+		"tokenPlaceholder": "123456:ABC-DEF...",
+		"noBots": "No bots registered yet.",
+		"chats": "Chats",
+		"noChats": "No chats found. Send a message to the bot first.",
+		"refreshChats": "Refresh",
+		"selectBot": "Select bot",
+		"selectChat": "Select chat",
+		"private": "Private",
+		"group": "Group",
+		"supergroup": "Supergroup",
+		"channel": "Channel"
+	},
 	"trackingConfig": {
 		"title": "Tracking Configs",
 		"description": "Define what events and assets to react to",