docs: update CLAUDE.md for Gitea migration and PDGA domain notes

- Fix runtime line (Node 22 slim, not Node 18 Alpine)
- Add Hosting line (Gitea, use tea not gh)
- Reflect new CI/CD flow (Gitea Actions, manual version bump, PACKAGES_TOKEN)
- Add PDGA Domain Notes section (rating cycle, predicted-rating algorithm,
  rate limits) so future sessions don't have to re-derive domain logic
- Note absence of test framework explicitly

CLAUDE.md

@@ -4,13 +4,14 @@ PDGA rating scraper and display app. Scrapes player ratings and course data from
 
 ## Tech Stack
 
-- **Runtime:** Node.js 18 (Alpine in Docker)
+- **Runtime:** Node.js 22 (slim/Debian-based in Docker)
+- **Hosting:** Gitea (`gitea.shcizo.se/shcizo/pdga-rating`) — use `tea` CLI for issues/PRs, not `gh`
 - **Server:** Express with EJS templates
 - **Database:** SQLite3 (file: `ratings.db`, Docker: `/app/data/ratings.db`)
 - **Frontend:** HTMX + vanilla JS (in `public/js/`)
 - **Scraping:** Puppeteer (with stealth plugin) + direct HTTP
 - **Logging:** Pino (JSON in production, pino-pretty in dev)
-- **CI/CD:** Release Please + Docker build/push to GHCR
+- **CI/CD:** Gitea Actions (tag-triggered docker build/push to `gitea.shcizo.se/shcizo/pdga-rating`)
 
 ## Project Structure
 
@@ -38,15 +39,25 @@ public/
 - `LOG_LEVEL=debug npm start` — Enable debug logging
 - `docker compose up` — Run via Docker
 
+**No test framework or lint setup** — `package.json` has only `start` and `dev` scripts. If adding either, document it here.
+
 ## Conventions
 
 - **Logging:** Use `require('./logger')` (or relative path). Never use `console.log/error` in backend code. Use appropriate Pino levels: `debug` for verbose/diagnostic data, `info` for operational status, `warn` for retries/degraded state, `error` for failures, `fatal` for startup crashes.
 - **Frontend JS:** `console.error` is fine in `public/js/` — runs in browser, no Pino.
-- **Commits:** Conventional commits (`feat:`, `fix:`, `refactor:`, `chore:`) — drives release-please.
+- **Commits:** Conventional commits (`feat:`, `fix:`, `refactor:`, `chore:`, `ci:`).
+- **Releases:** Manual version bump — edit `version` in `package.json` + `package-lock.json`, commit as `<version>`, tag `v<version>`, push commit + tag (`git push origin main v<version>`). Triggers `.gitea/workflows/docker-build.yml` which builds and pushes the image. Auth uses repo secret `PACKAGES_TOKEN` (PAT with `write:package`) — the auto-injected `GITEA_TOKEN` does not have effective registry access.
 - **Scraping:** Two strategies per entity: direct HTTP (fast, preferred) with Puppeteer fallback (stealth plugin for anti-bot). Rate limiting must be respected.
 - **Database:** Migrations run automatically on startup in `db.js`. Schema changes go there.
 - **Templates:** EJS with shared layout in `views/partials/`. Pages use HTMX for dynamic content loading.
 
+## PDGA Domain Notes
+
+- **Rating publication cycle:** PDGA officially recalculates ratings on the **second Tuesday of each month**. `getNextPDGAUpdateDate()` in `src/services/rating-calculator.js` computes this — round filtering uses it as cutoff.
+- **Predicted rating algorithm:** `calculatePredictedRating(roundRatings)` replicates PDGA's formula — 12-mo window (expands to 24 if <8 rounds), outlier removal at ≥7 rounds (2.5σ + 100pt threshold), double-weighting of recent 25% at ≥9 rounds. Returns `{rating, stdDev, debugLog}`.
+- **Rate limits:** `POST /api/refresh-round-history/:pdgaNumber` enforces a 24h cooldown per player (`src/routes/players.js`). Don't bypass — PDGA's site rate-limits aggressively.
+- **Round history refresh** uses Puppeteer (stealth plugin), other scraping prefers direct HTTP. Predicted rating is recomputed and stored on each refresh.
+
 ## Environment Variables
 
 | Variable | Default | Description |