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/providers/utils/inference/test_openai_mixin.py

@@ -10,10 +10,10 @@ from typing import Any
 from unittest.mock import AsyncMock, MagicMock, Mock, PropertyMock, patch
 
 import pytest
+from llama_stack_api.apis.inference import Model, OpenAIChatCompletionRequestWithExtraBody, OpenAIUserMessageParam
+from llama_stack_api.apis.models import ModelType
 from pydantic import BaseModel, Field
 
-from llama_stack.apis.inference import Model, OpenAIChatCompletionRequestWithExtraBody, OpenAIUserMessageParam
-from llama_stack.apis.models import ModelType
 from llama_stack.core.request_headers import request_provider_data_context
 from llama_stack.providers.utils.inference.model_registry import RemoteInferenceProviderConfig
 from llama_stack.providers.utils.inference.openai_mixin import OpenAIMixin

tests/unit/providers/utils/inference/test_prompt_adapter.py

@@ -4,10 +4,11 @@
 # This source code is licensed under the terms described in the LICENSE file in
 # the root directory of this source tree.
 
-from llama_stack.apis.inference import (
+from llama_stack_api.apis.inference import (
     OpenAIAssistantMessageParam,
     OpenAIUserMessageParam,
 )
+
 from llama_stack.models.llama.datatypes import RawTextItem
 from llama_stack.providers.utils.inference.prompt_adapter import (
     convert_openai_message_to_raw_message,

tests/unit/providers/utils/memory/test_vector_store.py

@@ -7,9 +7,9 @@
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
+from llama_stack_api.apis.common.content_types import URL, TextContentItem
+from llama_stack_api.apis.tools import RAGDocument
 
-from llama_stack.apis.common.content_types import URL, TextContentItem
-from llama_stack.apis.tools import RAGDocument
 from llama_stack.providers.utils.memory.vector_store import content_from_data_and_mime_type, content_from_doc
 
 

tests/unit/providers/utils/test_model_registry.py

@@ -34,8 +34,8 @@
 #
 
 import pytest
+from llama_stack_api.apis.models import Model
 
-from llama_stack.apis.models import Model
 from llama_stack.providers.utils.inference.model_registry import ModelRegistryHelper, ProviderModelEntry