feat(classify): tighten scoring with reaction co-occurrence and date negatives

强正向 reaction 需标题同时含 require_title；移除听/看等宽泛词，新增弱正向组；charge 命中>=2 记+3、==1 记+1；负向补充录播/录像并新增标题带日期强负向；时长仅在已命中 reaction/charge 时加权；discover 关键词改为单个咻咻满、pages=3、window_days=7，notify.min_score=4；同步示例配置、project.md/README 与相关测试。

config.example.json

@@ -77,33 +77,22 @@
     "candidate_ttl_days": 7
   },
   "discover": {
-    "keywords": ["咻咻满 reaction", "咻咻满 充电"],
-    "pages": 2,
-    "window_days": 14
+    "keywords": ["咻咻满"],
+    "pages": 3,
+    "window_days": 7
   },
   "notify": {
-    "min_score": 2,
+    "min_score": 4,
     "max_items_per_message": 10
   },
   "classify": {
     "require_title": "咻咻满",
     "self_mid": 37754047,
-    "positive": [
-      "reaction",
-      "re",
-      "反应",
-      "看",
-      "听",
-      "初听",
-      "首次",
-      "点评",
-      "锐评",
-      "路人",
-      "震惊",
-      "双人"
-    ],
-    "charge": ["充电", "加急", "专场"],
-    "negative": ["歌切", "切片", "纯享", "搬运", "完整版"],
+    "reaction": ["reaction", "反应"],
+    "charge": ["加急", "特急", "充电", "专场", "转场"],
+    "weak_positive": ["双人", "路人", "第一次", "首次"],
+    "negative": ["歌切", "切片", "纯享", "搬运", "完整版", "录播", "录像"],
+    "date_negative": true,
     "duration_boost": { "gt_30min": 1, "gt_60min": 2 }
   },
   "heat_weights": {