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

openapi-first/mcp/modules/openapi_first.templates.health_app.routes.json

@@ -1,16 +0,0 @@
-{
-  "module": "openapi_first.templates.health_app.routes",
-  "content": {
-    "path": "openapi_first.templates.health_app.routes",
-    "docstring": "OpenAPI operation handlers.\n\nThis module defines pure Python callables that implement OpenAPI\noperations for this service. Functions in this module are bound to HTTP\nroutes exclusively via OpenAPI ``operationId`` values.\n\nNo routing decorators, HTTP metadata, or framework-specific logic\nshould appear here. All request/response semantics are defined in the\nOpenAPI specification.\n\nThis module serves solely as an operationId namespace.",
-    "objects": {
-      "get_health": {
-        "name": "get_health",
-        "kind": "function",
-        "path": "openapi_first.templates.health_app.routes.get_health",
-        "signature": "<bound method Function.signature of Function('get_health', 16, 32)>",
-        "docstring": "Health check operation handler.\n\nThis function implements the OpenAPI operation identified by\n``operationId: get_health``.\n\nIt contains no routing metadata or framework-specific logic.\nRequest binding, HTTP method, and response semantics are defined\nexclusively by the OpenAPI specification.\n\nReturns\n-------\ndict\n    A minimal liveness payload indicating service health."
-      }
-    }
-  }
-}