docs: mark content-pipeline as deferred (niche-specific placeholder pending DB rewrite)

Decision: the JSON-based content-pipeline is optional and does not block cloning/
building a site. Rather than genericize the current JSON prompts, it will be
re-architected DB-managed via /api in a future session, with prompt genericization
folded into that. AGENTS.md now tells future agents not to genericize it prematurely.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SYHWLHihq3v9nxNwoPCKSn

AGENTS.md

@@ -103,7 +103,11 @@ Read this before relying on any subsystem:
   autoload, graceful CLI failures), but the **live DB + HTTP round-trip is UNVERIFIED**
   (never run on a served instance with a real database).
 - ⚠️ **Content pipeline** — prompts/scripts are **still niche-specific** (Medellín
-  restaurants); genericize them to `config.site.*` before use.
+  restaurants) AND the whole pipeline is **JSON-file-based** (`config.json`, `calendar.json`,
+  the `*-queue`/`*-scan` files, `state/`, `drafts/`). It is **slated for a DB-managed
+  rewrite** (that state moves into MySQL via the `/api` backend). **Do NOT invest in
+  genericizing the current JSON pipeline** — genericize the prompts as part of the DB
+  rewrite. Treat the pipeline as niche-specific placeholder scaffolding until then.
 
 ## Guardrails