feat: add CI pipeline with ESLint, refactor deploy with rollback + Telegram

- Add eslint.config.mjs (flat config, eslint-config-next@16 + TypeScript)
- Add .gitea/workflows/ci.yaml (lint, test:unit, build on all branches)
- Refactor deploy.yaml: needs: [ci] gate, Docker rollback tag, Telegram notifications
- Fix 3 pre-existing lint errors (empty interfaces, ts-ignore, require imports)

memento-note/package.json

@@ -25,7 +25,8 @@
     "test:unit:coverage": "vitest run --coverage",
     "test:migration": "vitest run tests/migration",
     "test:migration:watch": "vitest watch tests/migration",
-    "locales:agent-slide-themes": "node scripts/localize-agent-slide-themes-and-translate.mjs"
+    "locales:agent-slide-themes": "node scripts/localize-agent-slide-themes-and-translate.mjs",
+    "lint": "eslint"
   },
   "dependencies": {
     "@ai-sdk/anthropic": "^3.0.76",
@@ -136,6 +137,8 @@
     "@types/react-dom": "^19",
     "@vitest/coverage-v8": "^4.0.18",
     "concurrently": "^9.2.1",
+    "eslint": "^9.39.4",
+    "eslint-config-next": "^16.2.6",
     "prisma": "^5.22.0",
     "tailwindcss": "^4.0.0",
     "tsx": "^4.21.0",