fix(vfs): Z-04 — implement webdav quota report

src/vfs.rs

@@ -1127,10 +1127,28 @@ impl DavFileSystem for SanctumFs {
     }
 
     fn get_quota(&self) -> FsFuture<'_, (u64, Option<u64>)> {
+        if let Some(ref cfs) = self.carrier_fs {
+            return cfs.get_quota();
+        }
+
         Box::pin(async move {
-            // Virtueller Speicherplatz für Explorer: 1 TB
-            let total_capacity: u64 = 1024 * 1024 * 1024 * 1024;
-            Ok((0, Some(total_capacity)))
+            self.touch();
+            // Z-04: Echte Containergröße (physisch auf Disk) und freier Host-Speicher
+            let container_size = self.db.get_container_file_size().unwrap_or(0);
+            let used_bytes = if container_size > 0 {
+                container_size
+            } else {
+                self.db.get_total_used_size().unwrap_or(0)
+            };
+
+            let free_host_space = self
+                .db
+                .container_path()
+                .and_then(|p| crate::windows::get_available_disk_space(&p))
+                .unwrap_or(1024 * 1024 * 1024 * 1024); // Fallback: 1 TB
+
+            let total_capacity = used_bytes.saturating_add(free_host_space);
+            Ok((used_bytes, Some(total_capacity)))
         })
     }
 }