feat: serve docs flat at /<repo>/ with no redirects

- collect.py copies each repo's built site contents directly to a
  top-level <repo>/ dir (was libs|apis|wiki/<repo>/site nesting)
- nginx uses `index index.html lib/index.html api/index.html` so
  /dagpipe/ -> lib/index.html, /auth-server/ -> api/index.html are
  served internally with no redirects
- _index regenerates links against the flat layout
  (/dagpipe/lib/, /auth-server/api/, /mongo-ops/, /blog/...)
- config.yml static entries point at vendored blog/ + media-manager/
- Dockerfile copies per-repo dirs flat into the nginx html root
- removed stale libs/, apis/, wiki/, tutorials/ category trees

Dockerfile

@@ -29,16 +29,23 @@ COPY main.py core.py config.py collect.py config.yml ./
 COPY nginx.conf /etc/nginx/conf.d/default.conf
 RUN rm -f /etc/nginx/sites-enabled/default
 
-# --- collected documentation tree -----------------------------------------
+# --- collected documentation tree (flat, one dir per repo) -----------------
 COPY _index /usr/share/nginx/html/
-COPY libs   /usr/share/nginx/html/libs
-COPY apis   /usr/share/nginx/html/apis
-COPY wiki   /usr/share/nginx/html/wiki
-COPY tutorials /usr/share/nginx/html/tutorials
+COPY openapi-first /usr/share/nginx/html/openapi-first
+COPY doc-forge /usr/share/nginx/html/doc-forge
+COPY dagpipe /usr/share/nginx/html/dagpipe
+COPY mail-intake /usr/share/nginx/html/mail-intake
+COPY omniread /usr/share/nginx/html/omniread
+COPY py-jwt /usr/share/nginx/html/py-jwt
+COPY hexa /usr/share/nginx/html/hexa
+COPY mongo-ops /usr/share/nginx/html/mongo-ops
+COPY auth-server /usr/share/nginx/html/auth-server
+COPY blog /usr/share/nginx/html/blog
+COPY media-manager /usr/share/nginx/html/media-manager
 
 # --- MCP bundles -----------------------------------------------------------
 COPY mcp /app/mcp
 
 EXPOSE 8000 8001 8002 8003 8004 8005 8006 9000
 
-CMD ["python", "main.py"]
+CMD ["python", "main.py"]