Add SMB AAPL Extensions Phase 1-6 + VFS xattr support

Phase 1: AAPL Create Context negotiation
Phase 2: AFP_AfpInfo Stream structure (Finder info + creation time)
Phase 2.5: SMB Named Stream Backend (NamedStreamPath)
Phase 2.6: Backend Named Stream Support in handlers
Phase 2.7: VFS Extended Attributes (get/set/remove/list_xattr)
Phase 4: Time Machine share config (time_machine field)
Phase 5: Server/Volume Capabilities
Phase 6: macOS Unicode mapping (private range ↔ ASCII)

Tests: 174 smb-server tests pass, 52 VFS tests pass

markbase-core/Cargo.toml

@@ -74,6 +74,7 @@ ureq = "2.12"          # 輕量同步 HTTP 客戶端
 reqwest = { version = "0.12", optional = true }  # Async HTTP client for AsyncS3Vfs
 rayon = "1.10"          # Phase 4: 并行加密
 url = "2"              # URL 解析（rusty-s3 依賴）
+xattr = "1.0"          # Extended attributes support (AFP_AfpInfo, Time Machine)
 
 # === SMB/CIFS Client (Phase 1) ===
 smb2 = { path = "../vendor/smb2" }  # Pure-Rust SMB2/3 client library with pipelined I/O