Centralize negative prompt hygiene

tools/prompt_smoke.py

@@ -63,6 +63,7 @@ import pair_camera  # noqa: E402
 import pair_cast  # noqa: E402
 import pair_clothing  # noqa: E402
 import pair_rows  # noqa: E402
+import prompt_hygiene  # noqa: E402
 import prompt_builder as pb  # noqa: E402
 import pov_policy  # noqa: E402
 import row_normalization  # noqa: E402
@@ -2412,6 +2413,28 @@ def smoke_row_normalization_policy() -> None:
     _expect_no_duplicate_comma_items("row_normalization.pair.hard_row_negative", pair["hardcore_row"].get("negative_prompt"))
 
 
+def smoke_prompt_hygiene_policy() -> None:
+    merged = prompt_hygiene.combine_negative_text(
+        "bad anatomy, bad anatomy",
+        "low quality",
+        "bad anatomy",
+        "",
+    )
+    _expect(merged == "bad anatomy, low quality", "Prompt hygiene negative merge/dedupe changed")
+    _expect(
+        row_normalization.combined_negative("bad anatomy, bad anatomy", "low quality, bad anatomy") == merged,
+        "Row normalization negative merge should delegate to prompt hygiene",
+    )
+    _expect(
+        krea_formatter._combine_negative("bad anatomy, bad anatomy", "low quality", "bad anatomy") == merged,
+        "Krea negative merge should delegate to prompt hygiene",
+    )
+    _expect(
+        prompt_hygiene.sanitize_prose_text("Scene: . A sentence. A sentence.") == "A sentence.",
+        "Prompt hygiene prose cleanup changed",
+    )
+
+
 def smoke_row_rendering_policy() -> None:
     _expect(pb.SINGLE_TEMPLATE == row_rendering.SINGLE_TEMPLATE, "Prompt builder single template should delegate to row_rendering")
     _expect(
@@ -6662,6 +6685,7 @@ SMOKE_CASES: list[tuple[str, Callable[[], None]]] = [
     ("character_config_policy", smoke_character_config_policy),
     ("character_profile_policy", smoke_character_profile_policy),
     ("row_normalization_policy", smoke_row_normalization_policy),
+    ("prompt_hygiene_policy", smoke_prompt_hygiene_policy),
     ("row_rendering_policy", smoke_row_rendering_policy),
     ("row_role_graph_policy", smoke_row_role_graph_policy),
     ("row_assembly_policy", smoke_row_assembly_policy),