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>

uv.lock

@@ -1,5 +1,5 @@
 version = 1
-revision = 3
+revision = 2
 requires-python = ">=3.12"
 resolution-markers = [
     "(python_full_version >= '3.13' and platform_machine != 'aarch64' and sys_platform == 'linux') or (python_full_version >= '3.13' and sys_platform != 'darwin' and sys_platform != 'linux')",
@@ -1945,6 +1945,7 @@ dependencies = [
     { name = "httpx" },
     { name = "jinja2" },
     { name = "jsonschema" },
+    { name = "llama-stack-api" },
     { name = "openai" },
     { name = "opentelemetry-exporter-otlp-proto-http" },
     { name = "opentelemetry-sdk" },
@@ -2094,6 +2095,7 @@ requires-dist = [
     { name = "httpx" },
     { name = "jinja2", specifier = ">=3.1.6" },
     { name = "jsonschema" },
+    { name = "llama-stack-api", editable = "src/llama-stack-api" },
     { name = "llama-stack-client", marker = "extra == 'client'", specifier = ">=0.3.0" },
     { name = "openai", specifier = ">=2.5.0" },
     { name = "opentelemetry-exporter-otlp-proto-http", specifier = ">=1.30.0" },
@@ -2226,6 +2228,25 @@ unit = [
     { name = "together" },
 ]
 
+[[package]]
+name = "llama-stack-api"
+version = "0.1.0"
+source = { editable = "src/llama-stack-api" }
+dependencies = [
+    { name = "jsonschema" },
+    { name = "opentelemetry-exporter-otlp-proto-http" },
+    { name = "opentelemetry-sdk" },
+    { name = "pydantic" },
+]
+
+[package.metadata]
+requires-dist = [
+    { name = "jsonschema" },
+    { name = "opentelemetry-exporter-otlp-proto-http", specifier = ">=1.30.0" },
+    { name = "opentelemetry-sdk", specifier = ">=1.30.0" },
+    { name = "pydantic", specifier = ">=2.11.9" },
+]
+
 [[package]]
 name = "llama-stack-client"
 version = "0.3.0"