macOS Time Machine AFP monitoring: backup_time update on file modification

- Added afp_monitor.rs module to track AFP_AfpInfo backup_time
- Open struct now has 'modified' flag to track file modifications
- write.rs sets modified=true on successful write
- close.rs calls AfpMonitor::update_backup_time() on modified files
- create.rs calls AfpMonitor::init_afp_info() on new file creation
- AFP_AfpInfo stored as xattr com.apple.aapl.AfpInfo
- backup_time updated to current epoch time on modification

Also includes:
- LZ4 compression using lz4_flex crate
- Case sensitivity conditional on backend capabilities
- LDAP cfg feature gate fix
- RAID rebuild reconstruction implementation
- DOS attributes xattr persistence
- Snapshot disk persistence

Tests: 201 smb-server, 452 markbase-core (653 total)

vendor/smb-server/src/info_class.rs

@@ -337,7 +337,12 @@ pub fn encode_minimal_security_descriptor() -> Vec<u8> {
 /// bytes. The caller patches `NextEntryOffset` for chained entries.
 pub fn encode_dir_entry(class: u8, entry: &DirEntry, file_index: u64) -> Vec<u8> {
     let info = &entry.info;
-    let name_u16 = utf16le(&info.name);
+    // Apply reverse Catia mapping (ASCII -> Apple private-range chars) so that
+    // filenames containing chars illegal in SMB (e.g. `:`, `*`) roundtrip
+    // correctly for macOS clients.
+    let units: Vec<u16> = info.name.encode_utf16().collect();
+    let mapped = crate::unicode_mapping::map_ascii_to_private(&units);
+    let name_u16: Vec<u8> = mapped.iter().flat_map(|c| c.to_le_bytes()).collect();
     match class {
         FILE_DIRECTORY_INFORMATION => {
             // 64 bytes fixed + name
@@ -430,6 +435,7 @@ mod tests {
             change_time: 0x01D9_0000_0000_0000,
             is_directory: false,
             file_index: 1,
+            dos_attributes: 0,
         }
     }