chore: retire legacy custom CMS (content-editor.js) (MITHOME-93)

Removes the standalone, git-push-based content editor that predates
Payload CMS: content-editor.js, its scripts/cms-*.js modules, its
scripts/test-content-editor-*.js + scripts/test-cms-publish.js test
suite, scripts/markdown-render.js (only used by the editor's guide
renderer), the proto-side test doubles (cms-editor-client.test.ts,
cms-editor-shortcuts.test.ts), and the editor's own user guide
(docs/felhasznaloi-utmutato.md).

Kept: proto/src/content/*.json (still the source for
migrate-content-to-payload.ts and test fixtures for Header/Footer,
per MITHOME-96), proto/src/content/schema.js + scripts/test-content-schema.js
(still validate those JSON files), and docs/content-editor-recovery.md
(historical incident record, not user-facing tool docs).

Safety net before deletion (per user request): added
proto/scripts/export-content-snapshot.ts, a reusable Payload Local API
exporter, and ran it to produce docs/backups/payload-content-snapshot-*.json
— a full hu/en snapshot of every Global + LegalPages + Partners document
at the moment of retirement. Also confirmed no data-loss risk otherwise:
.content-backups/ (the editor's own gitignored backup dir) tops out at
2026-08-23, well before today's fresh migration run, and every JSON
edit ever made through the editor already exists as its own git commit
("content: frissítve a CMS-ből").

Updated dangling references: pre-deploy-tests.sh and
.agent/steering/testing.md (dropped the CMS test block),
.agent/workflows/deploy.md (publish flow is now Payload draft/publish,
not git push), CLAUDE.md + .agent/AGENTS.md (dropped the /cms-feature
workflow, deleted alongside it), README.md (stack description),
.agent/steering/development-rules.md (the guide-maintenance rule no
longer has a guide to maintain).

Verified: tsc, lint, proto unit tests (51 passed), root
test-content-schema.js, plane-sync unit tests, production build all
green after the deletion.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/pre-deploy-tests.sh

@@ -30,18 +30,13 @@ run "proto: lint (eslint)" bash -c "cd '${ROOT}/proto' && npm run lint"
 # ── Tartalom ─────────────────────────────────────────────────────────────────
 run "content: séma-validáció (minden JSON)" node "${ROOT}/scripts/test-content-schema.js"
 
-# ── CMS (content-editor) ─────────────────────────────────────────────────────
-run "cms: security guard (auth, CSRF, XFF)" node "${ROOT}/scripts/test-content-editor-security.js"
-run "cms: serializer regresszió (collect/reindex)" node "${ROOT}/scripts/test-content-editor-serializer.js"
-run "cms: atomikus mentés + backup" node "${ROOT}/scripts/test-content-editor-save.js"
-run "cms: optimista zárolás (409, hash-frissítés)" node "${ROOT}/scripts/test-content-editor-conflict.js"
-run "cms: verziók panel (diff, restore)" node "${ROOT}/scripts/test-content-editor-versions.js"
-run "cms: logó feltöltés (PNG, backup, audit)" node "${ROOT}/scripts/test-content-editor-logo.js"
-run "cms: login flow (session, Safari-scenariok)" node "${ROOT}/scripts/test-content-editor-login.js"
-run "cms: logout + rate-limit" node "${ROOT}/scripts/test-content-editor-logout.js"
-run "cms: guide endpoint + renderer" node "${ROOT}/scripts/test-content-editor-guide.js"
-run "cms: alsó sáv layout guard" node "${ROOT}/scripts/test-content-editor-bottombar.js"
-run "cms: publish parancs + integráció" node "${ROOT}/scripts/test-cms-publish.js"
+# ── CMS ──────────────────────────────────────────────────────────────────────
+# WHY nincs itt önálló CMS-tesztblokk: a régi egyedi CMS-t (content-editor.js
+# + scripts/cms-*.js + a hozzá tartozó test-content-editor-*.js szkriptek)
+# a Payload CMS-re állás (MITHOME-91/92) után leépítettük (MITHOME-93) — a
+# Payload admin felület saját, upstream teszteléssel rendelkezik, ezt itt nem
+# duplikáljuk. Payload collection/global konfigurációk saját tesztlefedettsége
+# külön feladat (MITHOME-96), még nincs implementálva.
 
 # ── Infra ────────────────────────────────────────────────────────────────────
 run "plane: sync unit tesztek" node --test "${ROOT}/scripts/plane/plane-sync.test.js"