fix: correct no hash the code does not check

validation: names what the code verifies. dosbox checks
MT32_CONTROL.ROM against nine sha1 and size; the truth's one md5 and
crc32 describe one of those revisions, and the export wrote them beside
System.dat's own sha1, a rom line no file satisfies, and replaced
Batocera's md5. pcsx_rearmed and DuckStation check scph1001.bin by size,
and the v2.0 md5 platforms name was replaced by v4.1's.

checked_hashes keeps a hash the code does not name only where a checked
hash pins one content. Otherwise it still pairs a renamed file but never
corrects or fills a value the platform wrote. Additions keep every hash.
diff_truth reads the same rule.

scripts/truth.py

@@ -602,9 +602,13 @@ def _hash_mismatch(t_entry: dict, s_entry: dict) -> dict | None:
 
     A value shared on any field settles it: the truth holds every revision a
     core accepts, and a profile may give one revision's sha1 without its md5.
+    A hash the code does not check contradicts nothing (checked_hashes).
     """
+    from exporter.baseline import checked_hashes
+
     if _hash_set(t_entry) & _hash_set(s_entry):
         return None
+    t_entry = checked_hashes(t_entry) or {}
     for h in ("sha1", "md5", "crc32"):
         t_hash = t_entry.get(h, "")
         s_hash = s_entry.get(h, "")