refactor(bot): remove old Express/EJS admin panel, add standalone health server (v1.2.7)

- Delete src/admin/ (1012 files: routes, views, public, auth) — old admin replaced by Next.js admin-next/
- Add src/healthServer.js: minimal HTTP /health on port 3001 for Docker healthcheck
- src/index.js uses startHealthServer instead of startAdminPanel
- Remove admin-dependent test (adminDeleteFeedback.test.js); 30 tests pass
- Remove ejs/express-ejs-layouts/express/cookie-parser/multer from deps
- admin-next: prisma binaryTargets for linux-arm64-openssl (arm64 prod)
- VERSION.md v1.2.7
- Bot adminHandlers (Telegram commands) kept — data preserved in shared SQLite

package.json

@@ -14,17 +14,12 @@
     "better-sqlite3": "^11.10.0",
     "bip39": "^3.1.0",
     "bitcoinjs-lib": "^6.1.6",
-    "cookie-parser": "^1.4.6",
     "csv-writer": "^1.6.0",
     "decompress": "^4.2.1",
     "dotenv": "^16.3.1",
     "ecpair": "^2.1.0",
-    "ejs": "^6.0.1",
     "ethereumjs-util": "^7.1.5",
-    "express": "^4.21.0",
-    "express-ejs-layouts": "^2.5.1",
     "hdkey": "^2.1.0",
-    "multer": "^2.2.0",
     "node-telegram-bot-api": "^0.64.0",
     "pino": "^8.21.0",
     "pino-pretty": "^13.1.3",