p3: blind titles, cap snippets, equalise k; abort cached dumps

Exempt title from the vendor-token check. Truncate snippets to 160
chars and clip all four packs to the same per-query k. run.py fails
cached replies with a rerun message instead of a config mismatch.

tests/bakeoff/run.py

@@ -108,6 +108,8 @@ def sift_one(base: str, key: str, query: str, k: int, timeout: float) -> dict:
 def check_sources(config: str, rows: list[dict]) -> str | None:
     want = EXPECTED_SOURCES[config]
     for i, row in enumerate(rows):
+        if row.get("cached"):
+            return f"query {i}: cached, rerun after the hour or change k"
         sizes = row.get("sizes") or {}
         ok = sizes.get("sources_ok") or []
         failed = sizes.get("sources_failed") or []
@@ -228,6 +230,10 @@ def self_test() -> int:
             bad = check_sources("searxng_brave", rows)
             if not bad:
                 raise AssertionError("mismatch not caught")
+            cached_rows = [{**rows[0], "cached": True, "sizes": {}}]
+            msg = check_sources("searxng", cached_rows)
+            if not msg or "cached, rerun after the hour or change k" not in msg:
+                raise AssertionError(msg)
             ht = hermes_tavily_one(host + "/search", "k", "one", 8, 5)
             if ht["data"]["web"][0]["description"] != "snippet":
                 raise AssertionError(ht)