feat: split API and provider specs into separate llama-stack-api pkg

Extract API definitions, models, and provider specifications into a
standalone llama-stack-api package that can be published to PyPI
independently of the main llama-stack server.

Motivation

External providers currently import from llama-stack, which overrides
the installed version and causes dependency conflicts. This separation
allows external providers to:

- Install only the type definitions they need without server dependencies
- Avoid version conflicts with the installed llama-stack package
- Be versioned and released independently

This enables us to re-enable external provider module tests that were
previously blocked by these import conflicts.

Changes

- Created llama-stack-api package with minimal dependencies (pydantic, jsonschema)
- Moved APIs, providers datatypes, strong_typing, and schema_utils
- Updated all imports from llama_stack.* to llama_stack_api.*
- Preserved git history using git mv for moved files
- Configured local editable install for development workflow
- Updated linting and type-checking configuration for both packages
- Rebased on top of upstream src/ layout changes

Testing

Package builds successfully and can be imported independently.
All pre-commit hooks pass with expected exclusions maintained.

Next Steps

- Publish llama-stack-api to PyPI
- Update external provider dependencies
- Re-enable external provider module tests

Signed-off-by: Charlie Doern <cdoern@redhat.com>

tests/unit/rag/test_rag_query.py

@@ -7,13 +7,13 @@
 from unittest.mock import AsyncMock, MagicMock
 
 import pytest
-
-from llama_stack.apis.tools.rag_tool import RAGQueryConfig
-from llama_stack.apis.vector_io import (
+from llama_stack_api.apis.tools.rag_tool import RAGQueryConfig
+from llama_stack_api.apis.vector_io import (
     Chunk,
     ChunkMetadata,
     QueryChunksResponse,
 )
+
 from llama_stack.providers.inline.tool_runtime.rag.memory import MemoryToolRuntimeImpl
 
 

tests/unit/rag/test_vector_store.py

@@ -12,13 +12,13 @@ from unittest.mock import AsyncMock, MagicMock
 
 import numpy as np
 import pytest
-
-from llama_stack.apis.inference.inference import (
+from llama_stack_api.apis.inference.inference import (
     OpenAIEmbeddingData,
     OpenAIEmbeddingsRequestWithExtraBody,
 )
-from llama_stack.apis.tools import RAGDocument
-from llama_stack.apis.vector_io import Chunk
+from llama_stack_api.apis.tools import RAGDocument
+from llama_stack_api.apis.vector_io import Chunk
+
 from llama_stack.providers.utils.memory.vector_store import (
     URL,
     VectorStoreWithIndex,