[Vibe] Add a compact AGENTS.md

AGENTS.md

@@ -0,0 +1,59 @@
+# AGENTS.md
+
+Oodikone is a Docker-based Node.js/TypeScript application for analysing University of Helsinki study data. Main areas are:
+
+- `services/frontend`: React, Vite, Redux Toolkit, and Material UI.
+- `services/backend`: Express, Sequelize, PostgreSQL, Redis, and BullMQ.
+- `services/shared`: shared types and utilities.
+- `updater/`: Sisu data workers and scheduler.
+- `e2e/`: Playwright tests; `cypress/` contains legacy tests.
+
+Use Node.js 24 or newer. Packages have separate dependencies and lockfiles. Install locally with
+`npm run install:local`, or use `npm run ci:local` for lockfile-exact installs. Docker uses host-mounted locks:
+update dependencies locally, then run `npm run ci:docker`; do not install in containers.
+
+## Development Rules
+
+- Read nearby code and tests before changing behavior; follow local conventions.
+- Keep changes focused and avoid unrelated formatting.
+- Reuse `services/shared` for cross-service types and utilities.
+- Never commit `.env` files, credentials, database dumps, or real student data.
+- Use anonymized data. Do not reset real databases, use destructive commands, or use real-data Docker profiles unless
+  explicitly required.
+- Treat migrations as production-impacting. They are in `services/backend/src/database/migrations_kone`,
+  `services/backend/src/database/migrations_user`, and `updater/sis-updater-worker/src/db/migrations`; test migration
+  changes against the relevant database service.
+
+## Local Commands
+
+```text
+npm run oodikone       # start the anonymized environment
+npm run both           # start Oodikone and the updater
+npm run docker:down    # stop containers
+docker compose ps      # show service status
+```
+
+The app runs at `http://localhost:3000` and Adminer at `http://localhost:5050`. Follow logs with
+`docker compose logs --follow frontend` or `docker compose logs --follow backend`.
+
+## Style And Verification
+
+- TypeScript/JavaScript: 2 spaces, single quotes, no semicolons, trailing commas where valid, 120-character lines.
+- Prefer explicit types at package boundaries, API payloads, Redux state, and database interfaces. Avoid `any` except
+  where needed to contain an untyped external API.
+- Run `npm run fmt` on changed source, `npm run lint`, and `npm run stylelint` when CSS changes. Do not bypass the
+  type-aware Oxlint/Oxfmt pre-commit hooks.
+- Run the narrowest relevant check, then broader checks as needed:
+  - Frontend: `npm run build --prefix services/frontend`, `npm run test:unit --prefix services/frontend`, or
+    `npm run test:component --prefix services/frontend`.
+  - Backend: `npm run build --prefix services/backend`, or `npm run test:unit --prefix services/backend`,
+    `npm run test:services --prefix services/backend`, or `npm run test:api --prefix services/backend`.
+  - Shared: `npm run test --prefix services/shared`.
+  - E2E: `npm run playwright -- e2e/<spec>.spec.ts`.
+    - If running `docker-compose.ci.yml` add env variable `CI=true` before the e2e npm command.
+      Otherwise some tests fail.
+- API, service, component, and E2E tests require Docker; start the relevant environment with `npm run oodikone:test`
+  or its documented profile. Report any checks that could not run and why.
+
+CI also validates Docker Compose files, Dockerfiles, shell scripts, workflows, and migrations. Keep such changes
+minimal and validate them locally where practical.