Files payloads moved to R2 in 041; this removes the remaining oCIS coupling:
- delete the oCIS WebDAV client; verifyWhileStreaming moves to its own
storage-agnostic module (verify-stream.ts)
- group-files: storage_key is the only payload source; legacy rows answer
'retired storage' instead of touching oCIS
- collective share: the ocis-resource item kind is gone (peertube links stay);
share-into-library was R2-backed since the previous commit
- import-drive endpoint removed (no web caller); import-chat (homeserver) stays
- web: Drive tab + embedded oCIS page removed; Library is the Files view
Legacy e2e rows (2) deleted; every remaining archive row is R2-backed.
