refactor: finetune through LLMClient interface + get_running_loop

- Add submit_finetune and get_finetune_status abstract methods to LLMClient base
- Implement both methods in ZhipuAIClient using asyncio.get_running_loop()
- Rewrite finetune_service to call llm.submit_finetune / llm.get_finetune_status
  instead of accessing llm._client directly, restoring interface encapsulation
- Replace asyncio.get_event_loop() with get_running_loop() in ZhipuAIClient._call
  and all four methods in RustFSClient (deprecated in Python 3.10+)
- Update test_finetune_service to mock the LLMClient interface methods as AsyncMocks
- Add two new tests in test_llm_client for submit_finetune and get_finetune_status

app/services/finetune_service.py

@@ -1,6 +1,4 @@
-import asyncio
-
-from app.core.exceptions import LLMCallError
+from app.clients.llm.base import LLMClient
 from app.core.logging import get_logger
 from app.models.finetune_models import (
     FinetuneStartRequest,
@@ -17,45 +15,21 @@ _STATUS_MAP = {
 }
 
 
-async def submit_finetune(req: FinetuneStartRequest, llm) -> FinetuneStartResponse:
-    """Submit a fine-tune job to ZhipuAI and return the job ID."""
-    loop = asyncio.get_event_loop()
-    try:
-        response = await loop.run_in_executor(
-            None,
-            lambda: llm._client.fine_tuning.jobs.create(
-                training_file=req.jsonl_url,
-                model=req.base_model,
-                hyperparameters=req.hyperparams or {},
-            ),
-        )
-        job_id = response.id
-        logger.info("finetune_submit", extra={"job_id": job_id, "model": req.base_model})
-        return FinetuneStartResponse(job_id=job_id)
-    except Exception as exc:
-        logger.error("finetune_submit_error", extra={"error": str(exc)})
-        raise LLMCallError(f"微调任务提交失败: {exc}") from exc
+async def submit_finetune(req: FinetuneStartRequest, llm: LLMClient) -> FinetuneStartResponse:
+    """Submit a fine-tune job via the LLMClient interface and return the job ID."""
+    job_id = await llm.submit_finetune(req.jsonl_url, req.base_model, req.hyperparams or {})
+    logger.info("finetune_submit", extra={"job_id": job_id, "model": req.base_model})
+    return FinetuneStartResponse(job_id=job_id)
 
 
-async def get_finetune_status(job_id: str, llm) -> FinetuneStatusResponse:
-    """Retrieve fine-tune job status from ZhipuAI."""
-    loop = asyncio.get_event_loop()
-    try:
-        response = await loop.run_in_executor(
-            None,
-            lambda: llm._client.fine_tuning.jobs.retrieve(job_id),
-        )
-        status_raw = response.status
-        status = _STATUS_MAP.get(status_raw, "RUNNING")  # conservative fallback
-        progress = getattr(response, "progress", None)
-        error_message = getattr(response, "error_message", None)
-        logger.info("finetune_status", extra={"job_id": job_id, "status": status})
-        return FinetuneStatusResponse(
-            job_id=job_id,
-            status=status,
-            progress=progress,
-            error_message=error_message,
-        )
-    except Exception as exc:
-        logger.error("finetune_status_error", extra={"job_id": job_id, "error": str(exc)})
-        raise LLMCallError(f"微调状态查询失败: {exc}") from exc
+async def get_finetune_status(job_id: str, llm: LLMClient) -> FinetuneStatusResponse:
+    """Retrieve fine-tune job status via the LLMClient interface."""
+    raw = await llm.get_finetune_status(job_id)
+    status = _STATUS_MAP.get(raw["status"], "RUNNING")
+    logger.info("finetune_status", extra={"job_id": job_id, "status": status})
+    return FinetuneStatusResponse(
+        job_id=raw["job_id"],
+        status=status,
+        progress=raw["progress"],
+        error_message=raw["error_message"],
+    )