fix: vendor per-kind sites in the hub; drop stale blog docs

- collect.py: when a kind points at the shared site root, copy only the
  per-kind subdir (site/lib -> <repo>/lib) instead of the whole site, so
  stray single-site build output never leaks into the hub
- Purge stale collected artifacts (404.html, assets/, search/, sitemaps,
  objects.inv, duplicate mcp/) from every repo dir, matching the cleaned
  source site/ roots
- Refresh collected output from source repos, incl. the khata-app app
- Remove the vendored Blog API docs (config.yml entry + blog/) and its card

py-jwt/mcp/nav.json

@@ -1,50 +0,0 @@
-[
-  {
-    "module": "jwtlib",
-    "resource": "doc://modules/jwtlib"
-  },
-  {
-    "module": "jwtlib.app",
-    "resource": "doc://modules/jwtlib.app"
-  },
-  {
-    "module": "jwtlib.exceptions",
-    "resource": "doc://modules/jwtlib.exceptions"
-  },
-  {
-    "module": "jwtlib.introspection",
-    "resource": "doc://modules/jwtlib.introspection"
-  },
-  {
-    "module": "jwtlib.models",
-    "resource": "doc://modules/jwtlib.models"
-  },
-  {
-    "module": "jwtlib.models.app",
-    "resource": "doc://modules/jwtlib.models.app"
-  },
-  {
-    "module": "jwtlib.models.common",
-    "resource": "doc://modules/jwtlib.models.common"
-  },
-  {
-    "module": "jwtlib.models.mongo",
-    "resource": "doc://modules/jwtlib.models.mongo"
-  },
-  {
-    "module": "jwtlib.models.security",
-    "resource": "doc://modules/jwtlib.models.security"
-  },
-  {
-    "module": "jwtlib.repository",
-    "resource": "doc://modules/jwtlib.repository"
-  },
-  {
-    "module": "jwtlib.security",
-    "resource": "doc://modules/jwtlib.security"
-  },
-  {
-    "module": "jwtlib.utils",
-    "resource": "doc://modules/jwtlib.utils"
-  }
-]