v6.4.63 release

• Fix SMB credential prompts and authentication failures on restricted shares, including a TV Leanback re-prompt loop
• Fix jcifs-ng filename handling for names containing '#' and prevent a root parent navigation loop
• Retry SMB directory listing automatically on stale connection/file handle errors
• Harden WebDAV security, range handling, directory listing, and memory usage
• Optimize WebDAV metadata lookups for faster browsing