Match MMS attachments on their recorded path and report the unreferenced ones

[abrignoni]

Three follow-ups to the SMS and MMS artifacts in smsmms.py.

• Attachment files are matched to part rows on the recorded part._data path (storage class, Android user, package, file name), not on the file name alone. On a two-user tree with same-named attachments the old join gave both users the first user's files; the new one gives each user its own.
• SMS Messages and MMS Messages now cite every database they read as the source path instead of the last one iterated, which on most images was the empty device-encrypted copy.
• New MMS Attachments artifact: every part row that records a file, joined to its message, plus the files under app_parts and parts that no part row references. Stored content type, sniffed type, size and a status column. Three of the 25 registered corpora carry between one and ten unreferenced image and video files that nothing reported before.

Rows of the three existing artifacts are identical before and after on all 25 corpora. Fixture extended for the new artifact.

🤖 Generated with Claude Code