feat(polish): add question guard, ABE routing, and flow trace

Harden polish so question drafts stay questions, add local density
routing with style-specific degrade, expand fun style packs, and add
end-to-end FlowTrace logging plus offline guard eval scripts.

Scripts/polish_audience_guard_eval.py

@@ -0,0 +1,124 @@
+#!/usr/bin/env python3
+"""Offline eval: RED Note polish must not invent an audience.
+
+Drafts that never address a crowd must come back without 姐妹们 / 集美们 /
+大家 style greetings or comment CTAs. Drafts that already speak to a group may
+keep that audience.
+
+Usage: python3 scripts/polish_audience_guard_eval.py [--samples N]
+"""
+
+import argparse
+import re
+import time
+from collections import Counter, defaultdict
+from pathlib import Path
+
+import polish_question_guard_eval as base
+
+AUDIENCE_TOKENS = (
+    "姐妹们",
+    "集美们",
+    "集美",
+    "宝子们",
+    "家人们",
+    "各位",
+    "大家好",
+    "姐妹",
+    "你们",
+    "大家",
+)
+CTA_TOKENS = ("评论区", "蹲一个", "蹲个", "在线等", "求反馈", "安利我", "宝藏吗")
+
+# (draft, addresses_a_group)
+CASES = [
+    ("我最近开始早睡感觉皮肤状态好了很多心情也好了", False),
+    ("这家店排队太久了味道一般不推荐", False),
+    ("这个防晒霜我用了挺好的不油夏天能用", False),
+    ("你觉得这个包怎么样", False),
+    ("今天这个会开得有点久但结论还算清楚", False),
+    ("这个防晒霜我用了感觉挺好的不油夏天用可以推荐给你们", True),
+    ("姐妹们这家店到底行不行求个真实反馈", True),
+]
+
+NEGATIVE_HOOKS = ("避雷", "踩坑", "翻车", "劝退", "别买", "会谢")
+# Drafts whose stance is positive; a negative hook would flip their meaning.
+POSITIVE_DRAFTS = {
+    "我最近开始早睡感觉皮肤状态好了很多心情也好了",
+    "这个防晒霜我用了挺好的不油夏天能用",
+    "这个防晒霜我用了感觉挺好的不油夏天用可以推荐给你们",
+}
+
+
+def flips_stance(draft: str, output: str) -> bool:
+    """A negative hook on a positive draft flips its meaning.
+
+    Only the opening line counts: mentioning 踩坑 later while inviting other
+    people's experiences does not reverse the author's own stance.
+    """
+    if draft not in POSITIVE_DRAFTS:
+        return False
+    hook = output.strip().splitlines()[0] if output.strip() else ""
+    return any(negative in hook for negative in NEGATIVE_HOOKS)
+
+
+def has_audience(text: str) -> bool:
+    return any(token in text for token in AUDIENCE_TOKENS)
+
+
+def has_cta(text: str) -> bool:
+    return any(token in text for token in CTA_TOKENS)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--samples", type=int, default=2)
+    parser.add_argument("--levels", default="light,medium,heavy")
+    args = parser.parse_args()
+
+    api_key = re.search(r'deepseek = "([^"]+)"', Path(base.KEYFILE).read_text()).group(1)
+    levels = [level.strip() for level in args.levels.split(",") if level.strip()]
+
+    tally: Counter[str] = Counter()
+    per_level: defaultdict[str, Counter] = defaultdict(Counter)
+    violations = []
+
+    for level in levels:
+        for draft, group in CASES:
+            prompt = base.build_prompt("builtin.xhs", level, draft)
+            for _ in range(args.samples):
+                try:
+                    output = base.call(api_key, prompt)
+                except Exception as error:  # noqa: BLE001 - eval script
+                    print(f"  request failed: {error}")
+                    continue
+
+                injected = (not group) and (has_audience(output) or has_cta(output))
+                flipped = flips_stance(draft, output)
+                if injected:
+                    verdict = "INVENTED_AUDIENCE"
+                elif flipped:
+                    verdict = "FLIPPED_STANCE"
+                else:
+                    verdict = "ok"
+                tally[verdict] += 1
+                per_level[level][verdict] += 1
+                if verdict != "ok":
+                    violations.append((level, verdict, draft, output))
+                flag = "" if verdict == "ok" else f"  <<< {verdict}"
+                print(f"[{level:6}] {draft[:14]}… -> {output!r}{flag}")
+                time.sleep(0.1)
+
+    print("\nSummary:", dict(tally))
+    for level in levels:
+        counts = per_level[level]
+        total = sum(counts.values())
+        print(f"  {level:6} ok={counts['ok']}/{total}")
+    if violations:
+        print("\nViolations:")
+        for level, verdict, draft, output in violations:
+            print(f"  [{level}][{verdict}] {draft} => {output!r}")
+
+
+if __name__ == "__main__":
+    main()