Initial commit: PRD, build tooling, and design mockups

Foodster is a self-hosted dinner log and meal suggester for one household.
Stage 1 (eating history) is in development; stage 2 (the suggester) follows
once there is enough history to weight against.

Replace the PRD's original stack (Nuxt, Postgres, Drizzle, Pico CSS) with
Go 1.27, net/http, templ, Datastar and SQLite — one static binary, no
Node.js in the build. Sections 3, 4, 5, 9, 10 and 11 are rewritten to match.

Record the decisions made while reviewing mockups:

- the UI is written in Finnish; PRD, code and comments stay English
- access is one shared password over HTTP Basic rather than open on the LAN
- images are CalVer vYYYYMMDD-N, built with Podman, run under Docker Compose
- registry coordinates live in .env, so no infrastructure detail is
  committed and the MIT publication option stays open

mockups/ holds standalone HTML design studies. log-fi.html is the current
one; the others are superseded exploration kept for reference.

README.md

@@ -0,0 +1,104 @@
+# Foodster
+
+A self-hosted dinner log and meal suggester for a single household. Record
+what the family actually ate, and — later — let the app propose seven dinners
+drawn from that history.
+
+The interface is in Finnish. The code, comments and documentation are in
+English.
+
+See [PRD.md](PRD.md) for the full specification.
+
+## Status
+
+**Stage 1 — eating history: in development.** The meal catalog and the daily
+log come first, because the suggester is worthless until there are a few
+weeks of real history to weight against.
+
+Stage 2 — the seven-meal suggester — starts once that history exists.
+
+## Stack
+
+One static Go binary. No Node.js, no bundler, no separate database server.
+
+| | |
+|---|---|
+| Language | Go 1.27 |
+| HTTP | stdlib `net/http` + `http.ServeMux` |
+| Views | [templ](https://templ.guide), server-rendered |
+| Interactivity | [Datastar](https://data-star.dev) — signals and DOM patching in one ~11 kB script |
+| Styling | hand-written CSS, `light-dark()` for themes |
+| Database | SQLite via `modernc.org/sqlite` (pure Go) |
+| Auth | HTTP Basic, one shared household password |
+| Runtime image | `FROM scratch` |
+
+## Quick start
+
+```sh
+cp .env.example .env     # then edit it
+make run                 # http://localhost:8080
+```
+
+`make` on its own lists every target:
+
+```
+make fix        gofmt, templ fmt, go mod tidy
+make lint       go vet, gofmt check, golangci-lint when installed
+make test       go test ./...
+make build      ./foodster
+make image      build and tag vYYYYMMDD-N (creates a git tag)
+make push       push the newest tag and :latest
+make release    image + push
+make up/down/logs   compose
+```
+
+## Configuration
+
+Everything is environment variables. `.env` is gitignored; start from
+`.env.example`.
+
+| Variable | Default | Purpose |
+|---|---|---|
+| `FOODSTER_PASSWORD` | *required* | Shared password. The app will not start without it. |
+| `FOODSTER_DB` | `/data/foodster.db` | SQLite file path. |
+| `TZ` | `Europe/Helsinki` | Used for every calendar-day calculation. |
+| `FOODSTER_REPO` | *required to build* | Image repository, no tag. |
+| `FOODSTER_TAG` | `latest` | Tag to run under compose. |
+| `FOODSTER_PORT` | `8080` | Host port to publish. |
+
+Set `TZ` in development too. Under UTC the date rolls over three hours late,
+which is exactly when dinner gets logged.
+
+## Deployment
+
+Images are built with Podman and run under Docker Compose on a LAN server.
+They are OCI images, so either engine works.
+
+```sh
+make release             # build, tag, push
+# on the server:
+docker compose pull && docker compose up -d
+```
+
+Versions are CalVer — `vYYYYMMDD-N`, where `N` is the Nth build that day. The
+running version is served at `GET /healthz`, which is the one route outside
+authentication.
+
+There is no database container. SQLite lives on a named volume, so a backup
+is a file copy.
+
+## Security
+
+Access is a single shared password over HTTP Basic — no accounts, no
+sessions. Credentials are compared in constant time, but Basic auth sends
+them in cleartext, so this belongs on a private LAN. Put TLS in front of it
+before exposing it anywhere else.
+
+## Mockups
+
+`mockups/` holds standalone HTML design studies. Open them directly in a
+browser; they are references, not part of the build.
+
+## License
+
+[MIT](LICENSE).