feat: Sprint 2 - 概率语义 + 轻量快照 + 数据库约束

P0-05: confidence → subjective_confidence 改名(15 文件)
       LLM 主观置信度与概率分离
P0-02: predictions 增加 cutoff_at + input_hash(轻量快照)
       MatchContext 暴露 match_dt
       单/多 Agent 路径均记录快照元数据
P2-05: 数据库 CHECK 约束
       - pred_home_goals >= 0
       - pred_away_goals >= 0
       - subjective_confidence 0~1
       - pred_1x2 IN (1,X,2)
       - mode IN (single,multi)
P2-06: limit 分页约束(ge=1, le=200)
P2-01: 新增 /health/ready 就绪检查

src/llm/predict.py

@@ -2,9 +2,11 @@
 from __future__ import annotations
 
 import functools
+import hashlib
 import logging
 import time
 from dataclasses import dataclass
+from datetime import datetime, timezone
 from pathlib import Path
 from threading import Lock
 
@@ -64,7 +66,7 @@ class PredictResult:
     pred_home_goals: float | None
     pred_away_goals: float | None
     pred_1x2: str | None
-    confidence: float | None
+    subjective_confidence: float | None
     reasoning: str | None
     context: str
     latency_ms: int | None
@@ -112,6 +114,10 @@ async def _predict_single(
     # 1. 拼上下文
     ctx = await build_context(match_id)
 
+    # 1.5 计算快照元数据(用于可复现性)
+    cutoff_at = ctx.match_dt  # 比赛时间 = 数据截止时间
+    input_hash = hashlib.sha256(ctx.text.encode("utf-8")).hexdigest()
+
     # 2. 拼 prompt(指定版本)
     template = _load_prompt_template(version)
     user_prompt = template.replace("{{context}}", ctx.text)
@@ -155,9 +161,11 @@ async def _predict_single(
             pred_home_goals=validated.pred_home_goals,
             pred_away_goals=validated.pred_away_goals,
             pred_1x2=validated.pred_1x2,
-            confidence=validated.confidence,
+            subjective_confidence=validated.subjective_confidence,
             reasoning=validated.reasoning,
             raw_response=resp.raw,
+            cutoff_at=cutoff_at,
+            input_hash=input_hash,
         )
         db.add(pred)
         await db.commit()
@@ -171,7 +179,7 @@ async def _predict_single(
             pred_home_goals=pred.pred_home_goals,
             pred_away_goals=pred.pred_away_goals,
             pred_1x2=pred.pred_1x2,
-            confidence=pred.confidence,
+            subjective_confidence=pred.subjective_confidence,
             reasoning=pred.reasoning,
             context=ctx.text,
             latency_ms=resp.latency_ms,