feat: run content checks profiles declare

validation: [romdir] walks a PS2 ROM directory the way the profile's
fork reads it, masked_sha1 hashes a file with a byte range cleared, and
size_multiple bounds a size to a granule. The resolver name steps, the
pack and manifest scans, the emulator expansion and verify call the same
content_fits. A PCSX2 companion is taken only beside an image that
passes, and a companion placeholder no longer seeds a scan of its own.

scripts/verify.py

@@ -400,7 +400,7 @@ def _build_expected(file_entry: dict, checks: list[str]) -> dict:
     if not checks:
         return expected
     if "size" in checks:
-        for key in ("size", "min_size", "max_size"):
+        for key in ("size", "min_size", "max_size", "size_multiple"):
             if file_entry.get(key) is not None:
                 expected[key] = file_entry[key]
     for hash_type in ("crc32", "md5", "sha1", "sha256"):