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.errors.json

@@ -1,23 +0,0 @@
-{
-  "module": "openapi_first.errors",
-  "content": {
-    "path": "openapi_first.errors",
-    "docstring": "# Summary\n\nExceptions for OpenAPI-first FastAPI applications.\n\nThis module defines a small hierarchy of explicit, intention-revealing\nexceptions used to signal contract violations between an OpenAPI\nspecification and its Python implementation.\n\nNotes:\n    **Design Principles:**\n\n        - Errors represent programmer mistakes, not runtime conditions.\n        - All errors are raised during application startup.\n        - Messages are actionable and suitable for CI/CD output.\n        - Exceptions are explicit rather than reused from generic built-ins.\n\n    These errors should normally cause immediate application failure.",
-    "objects": {
-      "OpenAPIFirstError": {
-        "name": "OpenAPIFirstError",
-        "kind": "class",
-        "path": "openapi_first.errors.OpenAPIFirstError",
-        "signature": "<bound method Class.signature of Class('OpenAPIFirstError', 22, 36)>",
-        "docstring": "Base exception for all OpenAPI-first enforcement errors.\n\nNotes:\n    **Responsibilities:**\n\n        - This exception exists to allow callers, test suites, and CI\n          pipelines to catch and distinguish OpenAPI contract violations\n          from unrelated runtime errors.\n        - All exceptions raised by the OpenAPI-first core should inherit\n          from this type."
-      },
-      "MissingOperationHandler": {
-        "name": "MissingOperationHandler",
-        "kind": "class",
-        "path": "openapi_first.errors.MissingOperationHandler",
-        "signature": "<bound method Class.signature of Class('MissingOperationHandler', 39, 77)>",
-        "docstring": "Raised when an OpenAPI operation cannot be resolved to a handler.\n\nNotes:\n    **Scenarios:**\n\n        - An OpenAPI operation does not define an `operationId`.\n        - An `operationId` is defined but no matching function exists in\n          the provided routes module.\n\n    **Guarantees:**\n\n        - This represents a violation of the OpenAPI-first contract and\n          indicates that the specification and implementation are out of\n          sync."
-      }
-    }
-  }
-}