docs: cut CLAUDE.md to rules-only (179 → 74 lines)

CLAUDE.md now carries only what must be known *before* opening a file:
hard rules, gotchas, and an entry-point table. Everything descriptive
moved to the doc that lives next to the code.

Moved out:
- stack versions, plugin roles, asset pipeline, nav shape, user/ repo
  tracking rules → docs/reference/architecture.md
- Playwright layout, config facts, auth-setup project, test account
  → docs/reference/testing.md (new)
- folder map, full make command list (build/test/demo/worktree targets
  that only existed in CLAUDE.md) → README.md
- dev/prod Twig settings table → already in docs/guides/deploy-cycle.md

Fixed while verifying, all of them descriptions that had drifted:
- demo fixtures were listed as italy-2026-demo + no-photos-demo; the
  actual folders are italy-2025 + italy-2026-demo
- the map engine was cited at js/src/maplibre-utils.js; it is
  js/maplibre-utils.js, a hand-authored file beside the bundles
- the build-output list omitted fonts/ and the generated
  templates/partials/weather-icons.html.twig, and did not flag that
  js/maplibre-utils.js and js/nav.js are sources living in js/
- README called user/ a "standalone git repo" (it is a submodule)
- docs/README.md linked to a non-existent working/production-todo.md
- git-sync-notes.md pointed at "CLAUDE.md §1", a section number that
  no longer exists

Net: ~17.1k → ~8.5k chars of always-loaded context.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/README.md

@@ -10,12 +10,13 @@
 
 **Checking project status?** → [`working/`](working/)
 - [Backlog](working/backlog.md)
-- [Production todo](working/production-todo.md)
+- [Bugs and fixes](working/bugs-and-fixes.md)
 - [QA results](working/qa/results.md)
 
 **Design or architecture decisions?** → [`reference/`](reference/)
 - [Design system](reference/design-system.md)
 - [Architecture overview](reference/architecture.md)
+- [Testing](reference/testing.md)
 
 ---