ci: local pre-push hook instead of GH Actions (private repo)

- remove .github/workflows/ci.yml
- add .githooks/pre-push: runs npm run test:all
- git config core.hooksPath .githooks (set)
- docs/DEVELOPMENT.md: document local pipeline

Private repo = no free Actions. Revisit when public.

docs/DEVELOPMENT.md

@@ -79,12 +79,23 @@ What each runs:
 
 Server tests use `--forceExit` (open WS handles). Tests spin server on random port, in-memory sqlite, tear down per test.
 
-### CI
+### Local pipeline (pre-push hook)
 
-`.github/workflows/ci.yml` runs on push/PR to `main` + `rework-backend`:
-- `npm ci`
-- `shared` tests
-- `server` tests
+Private repo = no free GitHub Actions. Tests run locally via git hook.
+
+`.githooks/pre-push` runs `npm run test:all` before every push.
+
+Enable on clone (do once):
+```bash
+git config core.hooksPath .githooks
+```
+
+Already configured on this checkout. Skip with:
+```bash
+git push --no-verify
+```
+
+Future: when repo goes public, free GH Actions viable. Then add `.github/workflows/ci.yml`.
 
 ## Build