chore(package): migrate to src/ layout (#3920)

Migrates package structure to src/ layout following Python packaging
best practices.

All code moved from `llama_stack/` to `src/llama_stack/`. Public API
unchanged - imports remain `import llama_stack.*`.

Updated build configs, pre-commit hooks, scripts, and GitHub workflows
accordingly. All hooks pass, package builds cleanly.

**Developer note**: Reinstall after pulling: `pip install -e .`

llama_stack/providers/remote/inference/bedrock/bedrock.py

@@ -1,142 +0,0 @@
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-# All rights reserved.
-#
-# This source code is licensed under the terms described in the LICENSE file in
-# the root directory of this source tree.
-
-import json
-from collections.abc import AsyncIterator
-
-from botocore.client import BaseClient
-
-from llama_stack.apis.inference import (
-    ChatCompletionRequest,
-    Inference,
-    OpenAIChatCompletionRequestWithExtraBody,
-    OpenAICompletionRequestWithExtraBody,
-    OpenAIEmbeddingsRequestWithExtraBody,
-    OpenAIEmbeddingsResponse,
-)
-from llama_stack.apis.inference.inference import (
-    OpenAIChatCompletion,
-    OpenAIChatCompletionChunk,
-    OpenAICompletion,
-)
-from llama_stack.providers.remote.inference.bedrock.config import BedrockConfig
-from llama_stack.providers.utils.bedrock.client import create_bedrock_client
-from llama_stack.providers.utils.inference.model_registry import (
-    ModelRegistryHelper,
-)
-from llama_stack.providers.utils.inference.openai_compat import (
-    get_sampling_strategy_options,
-)
-from llama_stack.providers.utils.inference.prompt_adapter import (
-    chat_completion_request_to_prompt,
-)
-
-from .models import MODEL_ENTRIES
-
-REGION_PREFIX_MAP = {
-    "us": "us.",
-    "eu": "eu.",
-    "ap": "ap.",
-}
-
-
-def _get_region_prefix(region: str | None) -> str:
-    # AWS requires region prefixes for inference profiles
-    if region is None:
-        return "us."  # default to US when we don't know
-
-    # Handle case insensitive region matching
-    region_lower = region.lower()
-    for prefix in REGION_PREFIX_MAP:
-        if region_lower.startswith(f"{prefix}-"):
-            return REGION_PREFIX_MAP[prefix]
-
-    # Fallback to US for anything we don't recognize
-    return "us."
-
-
-def _to_inference_profile_id(model_id: str, region: str = None) -> str:
-    # Return ARNs unchanged
-    if model_id.startswith("arn:"):
-        return model_id
-
-    # Return inference profile IDs that already have regional prefixes
-    if any(model_id.startswith(p) for p in REGION_PREFIX_MAP.values()):
-        return model_id
-
-    # Default to US East when no region is provided
-    if region is None:
-        region = "us-east-1"
-
-    return _get_region_prefix(region) + model_id
-
-
-class BedrockInferenceAdapter(
-    ModelRegistryHelper,
-    Inference,
-):
-    def __init__(self, config: BedrockConfig) -> None:
-        ModelRegistryHelper.__init__(self, model_entries=MODEL_ENTRIES)
-        self._config = config
-        self._client = None
-
-    @property
-    def client(self) -> BaseClient:
-        if self._client is None:
-            self._client = create_bedrock_client(self._config)
-        return self._client
-
-    async def initialize(self) -> None:
-        pass
-
-    async def shutdown(self) -> None:
-        if self._client is not None:
-            self._client.close()
-
-    async def _get_params_for_chat_completion(self, request: ChatCompletionRequest) -> dict:
-        bedrock_model = request.model
-
-        sampling_params = request.sampling_params
-        options = get_sampling_strategy_options(sampling_params)
-
-        if sampling_params.max_tokens:
-            options["max_gen_len"] = sampling_params.max_tokens
-        if sampling_params.repetition_penalty > 0:
-            options["repetition_penalty"] = sampling_params.repetition_penalty
-
-        prompt = await chat_completion_request_to_prompt(request, self.get_llama_model(request.model))
-
-        # Convert foundation model ID to inference profile ID
-        region_name = self.client.meta.region_name
-        inference_profile_id = _to_inference_profile_id(bedrock_model, region_name)
-
-        return {
-            "modelId": inference_profile_id,
-            "body": json.dumps(
-                {
-                    "prompt": prompt,
-                    **options,
-                }
-            ),
-        }
-
-    async def openai_embeddings(
-        self,
-        params: OpenAIEmbeddingsRequestWithExtraBody,
-    ) -> OpenAIEmbeddingsResponse:
-        raise NotImplementedError()
-
-    async def openai_completion(
-        self,
-        params: OpenAICompletionRequestWithExtraBody,
-    ) -> OpenAICompletion:
-        raise NotImplementedError("OpenAI completion not supported by the Bedrock provider")
-
-    async def openai_chat_completion(
-        self,
-        params: OpenAIChatCompletionRequestWithExtraBody,
-    ) -> OpenAIChatCompletion | AsyncIterator[OpenAIChatCompletionChunk]:
-        raise NotImplementedError("OpenAI chat completion not supported by the Bedrock provider")