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>

docs/openapi_generator/pyopenapi/generator.py

@@ -16,10 +16,10 @@ from typing import Annotated, Any, Dict, get_args, get_origin, Set, Union
 
 from fastapi import UploadFile
 
-from llama_stack.apis.datatypes import Error
-from llama_stack.strong_typing.core import JsonType
-from llama_stack.strong_typing.docstring import Docstring, parse_type
-from llama_stack.strong_typing.inspection import (
+from llama_stack_api.apis.datatypes import Error
+from llama_stack_api.strong_typing.core import JsonType
+from llama_stack_api.strong_typing.docstring import Docstring, parse_type
+from llama_stack_api.strong_typing.inspection import (
     is_generic_list,
     is_type_optional,
     is_type_union,
@@ -28,15 +28,15 @@ from llama_stack.strong_typing.inspection import (
     unwrap_optional_type,
     unwrap_union_types,
 )
-from llama_stack.strong_typing.name import python_type_to_name
-from llama_stack.strong_typing.schema import (
+from llama_stack_api.strong_typing.name import python_type_to_name
+from llama_stack_api.strong_typing.schema import (
     get_schema_identifier,
     JsonSchemaGenerator,
     register_schema,
     Schema,
     SchemaOptions,
 )
-from llama_stack.strong_typing.serialization import json_dump_string, object_to_json
+from llama_stack_api.strong_typing.serialization import json_dump_string, object_to_json
 from pydantic import BaseModel
 
 from .operations import (