feat: Docker audit + Telegram bot service + send UI

Docker:
- Harden docker-compose.yml: parameterized DB creds, required AUTH_SECRET,
  health checks, resource limits, network isolation, removed exposed DB port
- Add profiles (telegram/bot/full) so base 'docker compose up' needs only AUTH_SECRET
- Fix docker-entrypoint.sh: AUTH_SECRET startup guard
- Fix Dockerfile: copy prisma.config.ts + dotenv into production image
- Update .env.example with all new variables
- Update .dockerignore

Telegram Bot Service (bot/):
- TDLib-based bot using bot token auth (not HTTP Bot API)
- Commands: /search, /latest, /package, /link, /unlink, /subscribe, /unsubscribe
- pg_notify listener for send requests (bot_send) and new packages (new_package)
- Subscription-based notifications when matching packages arrive
- Dockerfile with multi-stage build (bookworm-slim for glibc/TDLib)

API & Database:
- Prisma: TelegramLink, BotSendRequest, BotSubscription models + migration
- POST /api/telegram/bot/send - queue package delivery to linked TG account
- GET /api/telegram/bot/send/[id] - poll send request status
- Server actions: generateTelegramLinkCode, unlinkTelegram, getBotSendHistory
- Worker: emit pg_notify('new_package') after creating packages

Frontend:
- Settings: TelegramLinkCard for account linking via one-time code
- STL table + drawer: SendToTelegramButton with send dialog and status polling
- Telegram admin: Bot Sends tab with delivery history table
- Shared SendHistoryRow type

README: Updated with bot docs, profiles, config vars, project structure

docker-entrypoint.sh

@@ -1,6 +1,14 @@
 #!/bin/sh
 set -e
 
+# Guard: refuse to start with the placeholder AUTH_SECRET
+if [ "$AUTH_SECRET" = "change-me-to-a-random-secret-in-production" ] || [ -z "$AUTH_SECRET" ]; then
+  echo "ERROR: AUTH_SECRET is not set or still uses the placeholder value."
+  echo "Generate one with: openssl rand -base64 32"
+  echo "Then set it in your .env file."
+  exit 1
+fi
+
 echo "Running database migrations..."
 npx prisma migrate deploy