local persistence for eval tasks (#453)

# What does this PR do?

- add local persistence for eval tasks
- follow https://github.com/meta-llama/llama-stack/pull/375

## Test Plan

1. fresh llama stack run
2. kill server
3. restart server: llama stack run

<img width="690" alt="image"
src="https://github.com/user-attachments/assets/3d76e477-b91a-43a6-86ea-8e3ef2d04ed3">

Using run.yaml
```yaml
eval_tasks:
  - eval_task_id: meta-reference-mmlu
    provider_id: meta-reference-0
    dataset_id: mmlu
    scoring_functions:
      - basic::regex_parser_multiple_choice_answer
```

## Before submitting

- [ ] This PR fixes a typo or improves the docs (you can dismiss the
other checks if that's the case).
- [ ] Ran pre-commit to handle lint / formatting issues.
- [ ] Read the [contributor
guideline](https://github.com/meta-llama/llama-stack/blob/main/CONTRIBUTING.md),
      Pull Request section?
- [ ] Updated relevant documentation.
- [ ] Wrote necessary unit or integration tests.

llama_stack/providers/inline/eval/meta_reference/config.py

@@ -3,7 +3,15 @@
 #
 # 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.eval import *  # noqa: F401, F403
+from llama_stack.distribution.utils.config_dirs import RUNTIME_BASE_DIR
+from llama_stack.providers.utils.kvstore.config import (
+    KVStoreConfig,
+    SqliteKVStoreConfig,
+)
+from pydantic import BaseModel
 
 
-class MetaReferenceEvalConfig(BaseModel): ...
+class MetaReferenceEvalConfig(BaseModel):
+    kvstore: KVStoreConfig = SqliteKVStoreConfig(
+        db_path=(RUNTIME_BASE_DIR / "meta_reference_eval.db").as_posix()
+    )  # Uses SQLite config specific to Meta Reference Eval storage