fix: remove unused sdk_detection module and clarify Google model format

Address review feedback:
- Delete sdk_detection.py which became dead code after switching to
  direct Header() params for SDK detection
- Remove sdk_detection from pyproject.toml py-modules since it should
  not be part of the public API surface
- Add comment clarifying that the Google models/{id} format is specific
  to the Gemini API and Vertex AI would need provider-aware translation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Sébastien Han <seb@redhat.com>

Author: leseb

src/llama_stack/core/routing_tables/models.py

@@ -196,6 +196,8 @@ async def anthropic_list_models(self) -> AnthropicListModelsResponse:
         )
 
     async def google_list_models(self) -> GoogleListModelsResponse:
+        # Uses the Gemini API "models/{id}" format. Vertex AI uses a different
+        # resource path and would need provider-aware translation if added.
         all_models = await self._get_all_models()
         google_models = [
             GoogleModelInfo(

src/llama_stack_api/pyproject.toml

@@ -77,7 +77,6 @@ py-modules = [
     "llama_stack_api.resource",
     "llama_stack_api.router_utils",
     "llama_stack_api.schema_utils",
-    "llama_stack_api.sdk_detection",
     "llama_stack_api.vector_stores",
     "llama_stack_api.version",
     "llama_stack_api.validators",