Implement SMB 3.x Lease support Phase 3

- CREATE handler parse RqLs create context
- Extract LeaseKey (16 bytes) + LeaseState (4 bytes)
- Check can_grant() before registration
- Register with LeaseManager
- Set Open.lease_key/lease_state fields

All 229 tests pass.

vendor/smb-server/src/handlers/create.rs

@@ -182,6 +182,49 @@ pub async fn handle(
         }).await;
     }
     
+    // Phase 3: Check for lease request in create contexts (SMB 3.x)
+    let (lease_key, lease_state) = if !req.create_contexts.is_empty() {
+        use crate::proto::messages::CreateContext;
+        let contexts = CreateContext::parse_chain(&req.create_contexts).unwrap_or_default();
+        
+        // Find RqLs (REQUEST_LEASE) context
+        let lease_ctx = contexts.iter().find(|ctx| ctx.name == CreateContext::NAME_RQLS);
+        
+        if let Some(ctx) = lease_ctx {
+            // Parse lease request (MS-SMB2 §2.2.13.2)
+            // Data format: LeaseKey (16 bytes) + LeaseState (4 bytes) + LeaseFlags (4 bytes)
+            if ctx.data.len() >= 24 {
+                let lease_key_bytes: [u8; 16] = ctx.data[0..16].try_into().unwrap_or([0; 16]);
+                let lease_state = u32::from_le_bytes([ctx.data[16], ctx.data[17], ctx.data[18], ctx.data[19]]);
+                
+                // Check if lease can be granted
+                if server.lease_manager.can_grant(lease_state).await {
+                    // Register lease
+                    use crate::oplock::LeaseEntry;
+                    server.lease_manager.register(LeaseEntry {
+                        lease_key: lease_key_bytes,
+                        lease_state,
+                        lease_flags: 0,
+                        file_id,
+                        path: path.clone(),
+                        session_id: hdr.session_id,
+                        tree_id: tree.id,
+                    }).await;
+                    
+                    (Some(lease_key_bytes), Some(lease_state))
+                } else {
+                    (None, None)
+                }
+            } else {
+                (None, None)
+            }
+        } else {
+            (None, None)
+        }
+    } else {
+        (None, None)
+    };
+    
     let open = Open::new(
         file_id,
         handle,
@@ -192,8 +235,17 @@ pub async fn handle(
         granted_oplock, // oplock_level
         req.share_access, // share_access
     );
+    
+    // Phase 3: Set lease fields if granted
     let open_arc = Arc::new(tokio::sync::RwLock::new(open));
-    tree.opens.write().await.insert(file_id, open_arc);
+    if lease_key.is_some() {
+        let mut open_mut = open_arc.write().await;
+        open_mut.lease_key = lease_key;
+        open_mut.lease_state = lease_state;
+        open_mut.lease_flags = Some(0);
+    }
+    
+    tree.opens.write().await.insert(file_id, open_arc.clone());
     drop(tree);
 
     let create_action = match intent {