docs(agent): refresh architecture/CLAUDE.md docs for Payload CMS (MITHOME-95)

The Content layer description across the AI-agent steering docs still
described the pre-migration JSON system as the live, current mechanism
— rule #1 in CLAUDE.md and the Content row in architecture.md
explicitly told future work (and future agent sessions) to edit
proto/src/content/pages/*.json directly, which the live site hasn't
read since MITHOME-91.

Rewrote, per the ticket's named targets:
- .agent/steering/architecture.md: system overview, the Content layer
  table row, rule #1, and the Content Management code example now
  describe Payload Globals/Collections + the payload-content.ts Local
  API adapter, with /admin as the editing surface.
- CLAUDE.md: Stack line now names Payload CMS, rule #1 rewritten the
  same way, and the project-structure tree gets the (frontend)/(payload)
  route groups, globals/, collections/, and payload.config.ts that were
  entirely missing from it.

Also fixed directly-adjacent staleness found while doing this pass —
same "how is content edited" documentation debt, just not literally
named in the ticket:
- .agent/AGENTS.md: same project-structure tree gap as CLAUDE.md.
- .agent/workflows/new-feature.md: step 3 told contributors to edit
  the JSON file directly; now points at the Payload config + admin.
- .agent/workflows/review.md: the example "flag hardcoded text" review
  comment suggested moving it into the JSON file.
- .agent/steering/development-rules.md: the TRADEOFF code example
  literally used "JSON content management vs CMS" as a live open
  decision — that decision is resolved, updated the example to match.
- README.md: the entire "Tartalomkezelés" section and a "CMS
  Publikálás gomb" paragraph described the retired content-editor.js
  workflow (git-push-based publish, JSON directory tour) as current;
  also dropped a dead link to docs/felhasznaloi-utmutato.md, deleted
  in MITHOME-93.

Doc-only change, no proto/ source touched — no gate to run beyond a
sanity re-read of each edited file.

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

README.md

@@ -39,32 +39,33 @@ scripts/pre-deploy-tests.sh
 ./deploy.sh production                  # éles (szerveren, staging ellenőrzése után)
 ```
 
-A CMS „Publikálás" gombja szintén commitol + pushol + deployol (csak a beállított környezetre). Részletek: `.agent/workflows/deploy.md`, `docs/helyi-staging-deploy.md`.
+A Payload admin (`/admin`) draft/publish + verziózás munkafolyamata (MITHOME-92) nem jár git commit-tal vagy automatikus deployjal — a tartalom közvetlenül a MongoDB-be íródik. Kódváltozás (Globals/Collections séma, frontend) továbbra is a fenti git-alapú deploy folyamaton megy át. Részletek: `.agent/workflows/deploy.md`.
 
 ## Tartalomkezelés
 
-A weboldal szövegei és a CMS a `proto/src/content/` JSON-fájljaiból jönnek:
+A weboldal szövegei Payload CMS Globals/Collections mezőkben élnek, az ügyfél a `/admin` felületen szerkeszti őket:
 
 ```
-proto/src/content/
-├── schema.js        # közös séma-validátor (Next + CMS)
-├── types.ts         # TypeScript típusok
-├── index.ts         # tartalom-betöltő
-├── common.json      # közös szövegek (gombok, lábléc, a11y)
-└── pages/           # oldalankénti tartalom (home, about, services, …)
+proto/src/globals/       # Home, About, Services, Contact, Common
+proto/src/collections/   # LegalPages, Partners, Media, ContactSubmissions, Users
+proto/src/payload.config.ts
 ```
 
-Használat:
+Használat Server Component-ből (a Payload Local API-n keresztül):
 
 ```typescript
-import { content, getPageContent } from '@/content'
-const about = content.pages.about
+import { getAboutContent } from '@/lib/payload-content'
+const about = await getAboutContent(locale) // locale: 'hu' | 'en'
 ```
 
+A régi, JSON-alapú content rendszer (`proto/src/content/`) már csak a
+`migrate-content-to-payload.ts` seed-script forrásaként és néhány
+komponens-teszt fixture-jeként él tovább — élő oldal nem olvassa (MITHOME-91/93).
+
 ## Dokumentáció
 
 - **Agent-szabályok**: `.agent/AGENTS.md`, `.agent/steering/`, `.agent/workflows/`
-- **CMS felhasználói útmutató**: `docs/felhasznaloi-utmutato.md` (a CMS-ben a ❓ Súgó is ezt rendereli)
+- **nginx vhost-ok**: `docs/nginx-vhosts.md`
 - **Plane szinkron**: `PLANE-SYNC-GUIDE.md`
 - **Staging deploy**: `docs/helyi-staging-deploy.md`
 - **Gitea runner**: `docs/gitea-runner-telepites.md`