refactor: _theme_clusters 迁入 narrative_axis 并以注入消除反向依赖

theme_clusters/theme_names 经参数注入 THEME_RULES 与 skill_id_fn,
避免 generate.py 的循环 import(T3,为拆分 generate_report 铺路)。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

daily/narrative_axis.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 import json
 import logging
 import random
+from collections import defaultdict
 from datetime import datetime, timedelta
 from typing import Any
 
@@ -101,3 +102,48 @@ def enforce_narrative_axis(trends: dict[str, Any], axis: str) -> dict[str, Any]:
     out = dict(trends)
     out["narrative_axis"] = axis
     return out
+
+
+def theme_clusters(
+    feed: dict[str, Any],
+    *,
+    limit: int = 5,
+    theme_rules: list[tuple[str, str, list[str]]],
+    skill_id_fn: Any,
+) -> list[tuple[str, list[str]]]:
+    """按 THEME_RULES 把 feed 的 topTrending/topHot 聚成 (主题, 示例列表)。
+
+    从 generate.py 迁入（原私有 _theme_clusters）。theme_rules 与 skill_id_fn
+    由调用方注入，避免对 generate.py 的反向依赖（防循环 import）。
+    """
+    buckets: dict[str, list[str]] = defaultdict(list)
+    seen: set[str] = set()
+    for board in ("topTrending", "topHot"):
+        for item in feed.get(board, [])[:20]:
+            item_id = skill_id_fn(item)
+            if item_id in seen:
+                continue
+            seen.add(item_id)
+            haystack = " ".join(
+                [item.get("title", ""), item.get("source", ""), item.get("description", "")]
+            ).lower()
+            for _icon, theme, keywords in theme_rules:
+                if any(k in haystack for k in keywords):
+                    label = f"**{item.get('title')}** (`{item.get('source')}`)"
+                    if label not in buckets[theme]:
+                        buckets[theme].append(label)
+                    break
+    return [(theme, examples[:limit]) for theme, examples in buckets.items() if examples]
+
+
+def theme_names(
+    feed: dict[str, Any],
+    *,
+    theme_rules: list[tuple[str, str, list[str]]],
+    skill_id_fn: Any,
+    limit: int = 3,
+) -> list[str]:
+    """仅取主题名（不含 markdown 示例），供「今日看点/theme_line」回退文案。"""
+    return [theme for theme, _ in theme_clusters(
+        feed, theme_rules=theme_rules, skill_id_fn=skill_id_fn
+    )][:limit]