Scaffold Docker-only Node 24 + TypeScript EJS web backend

AGENTS.md

@@ -0,0 +1,38 @@
+# AGENTS.md
+
+Guidance for AI agents and contributors working in this repo. Read `README.md` for
+commands and layout.
+
+## Project priorities (do not erode)
+
+1. **Simplicity** — prefer the smallest, most readable solution.
+2. **Few dependencies** — the only runtime dep is `ejs`. Prefer the Node standard
+   library. Justify any new dependency; do not add frameworks.
+3. **Strict TypeScript** — `tsconfig.json` is strict (incl. `noUncheckedIndexedAccess`,
+   `exactOptionalPropertyTypes`, `verbatimModuleSyntax`). Keep it that way.
+
+## Docker only — no host tooling
+
+**Everything** (install, typecheck, test, run, build, deploy) goes through Docker /
+Docker Compose. **Never run `node`, `npm`, or `tsc` on the host.**
+
+```bash
+docker compose up                                # dev server, live reload
+docker compose run --rm web npm run typecheck    # strict type check
+docker compose run --rm web npm test             # tests
+docker compose -f docker-compose.yml up --build -d   # production
+```
+
+## Rules
+
+- Node 24 runs `.ts` directly (type stripping). Keep all TypeScript **erasable**
+  (`erasableSyntaxOnly` is on): no `enum`, `namespace`, parameter properties, or
+  decorators. Import local modules with their `.ts` extension.
+- **No build step** and no compiled artifacts — do not add a bundler or `tsc` emit.
+- Before finishing a change, run the typecheck and tests above; both must pass.
+- Tests use the built-in `node --test` runner — no test framework dependency.
+- English everywhere. Keep code comments short and information-dense.
+- Pin all dependencies and Docker images to exact, human-readable **semantic
+  versions** — never ranges (`^`, `~`) and never digests/hashes. npm deps are kept
+  exact by `.npmrc` (`save-exact=true`) + `npm ci`; the base image by tag (e.g.
+  `node:24.16.0-alpine3.24`).