ROMFS CHECKSUMS

```
Description: The ROMFS file system does not verify checksums on either
volume header on on the individual files.
Status: Open
Priority: Low. I have mixed feelings about if NuttX should pay a
performance penalty for better data integrity.
```

The issue identifies ROMFS volume headers and individual files but names no implementation files or tests. Start by locating the ROMFS implementation and existing checksum support; determine the intended verification scope and performance expectations. Done means checksum verification is implemented for the agreed ROMFS data and covered by appropriate tests.

Written by the indexing model from the issue text.