api: serve interactive OpenAPI docs at /api/docs (offline) + llms.txt

Generate docs/openapi.json (3.1, 362 operations) from the API inventory via
scripts/gen_openapi.py, and serve it with a self-hosted Redoc bundle at
/api/docs - no CDN, works on the air-gapped box. Also serve docs/llms.txt (a
concise LLM entrypoint) at /api/docs/llms.txt. New core 'docs' blueprint;
staticdocs/ excluded from the naming check (vendored minified JS).

scripts/check-naming-and-style.sh

@@ -25,6 +25,7 @@ EXCLUDES=(
     --exclude-dir=dist
     --exclude-dir=.git
     --exclude-dir=versions
+    --exclude-dir=staticdocs
 )
 
 INCLUDES_CODE=(