Implement SMB Oplocks Phase 4+6

Phase 4: CREATE Handler dynamic oplock granting
- Use OplockManager.can_grant() to determine oplock level
- Register OplockEntry if oplock granted
- Support ShareAccess compatibility checking
- Grant Level II if exclusive/batch oplock exists

Phase 6: CLOSE Handler oplock cleanup
- Unregister from OplockManager when file closed
- Only unregister if oplock_level > 0

All 229 tests pass.

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

@@ -46,7 +46,7 @@ const FILE_OPENED: u32 = 0x0000_0001;
 const FILE_CREATED: u32 = 0x0000_0002;
 
 pub async fn handle(
-    _server: &Arc<ServerState>,
+    server: &Arc<ServerState>,
     conn: &Arc<Connection>,
     hdr: &Smb2Header,
     body: &[u8],
@@ -154,14 +154,39 @@ pub async fn handle(
     let tree = tree_arc.write().await;
     let file_id = tree.alloc_file_id();
     
-    // Phase 4: Oplock support - determine oplock level
-    let granted_oplock = 0; // Phase 1 placeholder (will be dynamic in Phase 4)
+    // Phase 4: Oplock support - use OplockManager to determine granted level
+    let requested_oplock = req.requested_oplock_level;
+    let granted_oplock = if requested_oplock == 0 {
+        0 // No oplock requested
+    } else {
+        // Check with OplockManager
+        server.oplock_manager.can_grant(
+            &path,
+            requested_oplock,
+            req.share_access,
+            if want_write { granted } else { Access::Read },
+        ).await.unwrap_or(0)
+    };
+    
+    // Register with OplockManager if oplock granted
+    if granted_oplock > 0 {
+        use crate::oplock::OplockEntry;
+        server.oplock_manager.register(&path, OplockEntry {
+            file_id,
+            tree_id: tree.id,
+            session_id: hdr.session_id,
+            oplock_level: granted_oplock,
+            share_access: req.share_access,
+            granted_access: if want_write { granted } else { Access::Read },
+            connection_id: 0, // Will be tracked in Phase 3
+        }).await;
+    }
     
     let open = Open::new(
         file_id,
         handle,
         if want_write { granted } else { Access::Read },
-        path,
+        path.clone(),
         info.is_directory,
         delete_on_close,
         granted_oplock, // oplock_level