Implement Share Management UI (Phase 11 P0 #2)

Share Management Features:
- Shares.vue: Complete share CRUD interface
- Tauri commands: 5 share endpoints
- In-memory share storage (lazy_static)

UI Components:
- Share list table (name, path, protocol, users, permissions)
- Create share dialog (name, path, protocol, users, permissions)
- Edit share dialog (path, protocol, users, permissions)
- Delete share confirmation
- Test connection button

Tauri Commands:
- list_shares: List all shares
- create_share: Create share + create directory if needed
- update_share: Update share config
- delete_share: Remove share from list
- test_share_connection: Test share path exists

Supported Protocols:
- SMB/CIFS (default)
- SFTP
- WebDAV
- S3

Router:
- Added /shares route

Home.vue:
- Added Share Management card

Build: ✅ Tauri + markbase-core
Tests: 495 markbase-core + 201 smb-server

markbase-tauri/src-tauri/src/main.rs

@@ -47,6 +47,11 @@ fn main() {
             update_auth_user,
             delete_auth_user,
             reset_auth_password,
+            list_shares,
+            create_share,
+            update_share,
+            delete_share,
+            test_share_connection,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");