chore(cms): disable Payload's anonymous telemetry

Payload sends anonymous usage telemetry to its own servers by default.
The site is self-hosted specifically so the client's data never leaves
our own infrastructure (see the legal/GDPR discussion in chat) — that
reasoning extends to Payload's own runtime telemetry too, so opt out
via telemetry: false in payload.config.ts.

Verified: build and dev server produce no telemetry notice, and the
admin dashboard's network requests (checked in a real browser) are
all to localhost — no outbound telemetry calls.

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

proto/src/payload.config.ts

@@ -49,5 +49,10 @@ export default buildConfig({
     url: process.env.MONGODB_URI || '',
   }),
 
+  // WHY: Payload sends anonymous usage telemetry to its own servers by
+  // default — GDPR-tudatosan kikapcsolva, mivel a projekt self-hosted és
+  // az ügyfél adatai nem hagyhatják el a saját infrastruktúránkat.
+  telemetry: false,
+
   sharp,
 })