Implement Week 7 Remote Origins with Oracle fixes
- Add credentials.rs with CredentialStore, redacted Debug (session_token shows [REDACTED])
- Add nfs.rs with ESTALE retry using Fn closure, 5s health timeout
- Add smb.rs with ENOTCONN retry handling, 5s health timeout
- Add s3.rs/sftp.rs feature-gated stubs with security documentation
- Add error variants: S3, Sftp, Timeout, Credential, NfsStaleHandle
- Fix delta.rs unused imports
Oracle fixes applied:
- SMB retry_on_disconnect for ENOTCONN (errno 107)
- session_token Debug shows [REDACTED] when Some, None otherwise
- NFS/SMB health checks wrapped with tokio::time::timeout(5s)
102 tests pass, 0 warnings.
Alexander
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