refactor: Add ProviderContext for a flexible storage directory

- Introduce ProviderContext class to decouple provider storage paths from absolute paths
- Add storage_dir attribute to StackRunConfig to accept CLI options
- Implement storage directory resolution with prioritized fallbacks:
  1. CLI option (--state-directory)
  2. Environment variable (LLAMA_STACK_STATE_DIR)
  3. Default distribution directory
- Standardize provider signatures to follow context, config, deps pattern
- Update provider implementations to use the new context-based approach
- Add comprehensive tests to verify state directory resolution

llama_stack/providers/inline/safety/code_scanner/__init__.py

@@ -6,12 +6,14 @@
 
 from typing import Any
 
+from llama_stack.providers.datatypes import ProviderContext
+
 from .config import CodeScannerConfig
 
 
-async def get_provider_impl(config: CodeScannerConfig, deps: dict[str, Any]):
+async def get_provider_impl(context: ProviderContext, config: CodeScannerConfig, deps: dict[str, Any]):
     from .code_scanner import MetaReferenceCodeScannerSafetyImpl
 
-    impl = MetaReferenceCodeScannerSafetyImpl(config, deps)
+    impl = MetaReferenceCodeScannerSafetyImpl(context, config, deps)
     await impl.initialize()
     return impl

llama_stack/providers/inline/safety/code_scanner/code_scanner.py

@@ -15,6 +15,7 @@ from llama_stack.apis.safety import (
     ViolationLevel,
 )
 from llama_stack.apis.shields import Shield
+from llama_stack.providers.datatypes import ProviderContext
 from llama_stack.providers.utils.inference.prompt_adapter import (
     interleaved_content_as_str,
 )
@@ -30,8 +31,10 @@ ALLOWED_CODE_SCANNER_MODEL_IDS = [
 
 
 class MetaReferenceCodeScannerSafetyImpl(Safety):
-    def __init__(self, config: CodeScannerConfig, deps) -> None:
+    def __init__(self, context: ProviderContext, config: CodeScannerConfig, deps) -> None:
+        self.context = context
         self.config = config
+        self.deps = deps
 
     async def initialize(self) -> None:
         pass