fix(P0-03): Prediction 幂等指纹——只追加,不覆盖

_upsert_prediction 改为 _insert_or_find_by_fingerprint:
- 同 input_hash → 返回已有行(绝不 UPDATE pred_/reasoning/agent_outputs)
- 不同 input_hash → INSERT 新行

input_hash 升级为规范 JSON SHA-256,捕获:match_id, cutoff, prompt_version,
prompt_hash, system_prompt_hash, provider, model, mode, run_type, temperature,
context_hash, agent_ids。移除旧 (match, provider, model, mode, run_type) 唯一约束,
改为 partial unique index(WHERE input_hash IS NOT NULL,兼容旧 NULL 数据)。

三条路径(single/multi/baseline)统一传足指纹字段。
迁移 0024 + 测试 test_p0_prediction_fingerprint(10/10);全量 295 通过。

src/llm/baseline.py

@@ -5,14 +5,15 @@
 """
 from __future__ import annotations
 
+import hashlib
 import logging
-from datetime import datetime
+from datetime import datetime, timedelta, timezone
 
 from sqlalchemy import case, func, select
 
 from src.db.base import AsyncSession, AsyncSessionLocal
 from src.db.models import Match
-from src.llm.predict import PredictResult, _upsert_prediction
+from src.llm.predict import PredictResult, _insert_or_find_by_fingerprint
 
 logger = logging.getLogger(__name__)
 
@@ -97,8 +98,23 @@ async def predict_baseline(
     else:
         pred_1x2 = "X"
 
+    # P0-03: 基线指纹——基于主客场场均进球数据(context_hash) + 截止时间
+    context_hash = hashlib.sha256(
+        f"{home_avg:.4f}:{away_avg:.4f}:{before.isoformat() if before else 'none'}".encode("utf-8")
+    ).hexdigest()
+
     values = {
+        "match_id": match_id,
+        "provider": "baseline",
+        "model": "baseline",
+        "mode": "baseline",
+        "run_type": "live",
         "prompt_version": "baseline_v1",
+        "prompt_hash": hashlib.sha256(b"baseline_v1").hexdigest(),
+        "system_prompt_hash": hashlib.sha256(b"baseline").hexdigest(),
+        "temperature": 0.0,
+        "context_hash": context_hash,
+        "agent_ids": [],
         "prompt_tokens": 0,
         "completion_tokens": 0,
         "latency_ms": 0,
@@ -114,17 +130,9 @@ async def predict_baseline(
         "status": "success",
     }
 
-    # P3-2:服务层落库,回填真实 prediction_id(与 single/multi 统一)。
+    # P0-03:服务层幂等插入,回填真实 prediction_id(与 single/multi 统一)。
     async with get_uow() as session:
-        pred = await _upsert_prediction(
-            session,
-            match_id=match_id,
-            provider_name="baseline",
-            model="baseline",
-            mode="baseline",
-            run_type="live",
-            values=values,
-        )
+        pred = await _insert_or_find_by_fingerprint(session, values=values)
         prediction_id = pred.id
 
     return PredictResult(