feat(network): add connect tool and middle-pan

frontend/src/components/network/NetworkCanvas.tsx

@@ -99,17 +99,22 @@ export function NetworkCanvas({
         edgeTypes={edgeTypes}
         defaultEdgeOptions={{ type: 'connection' }}
         edgesReconnectable
+        connectOnClick={interactionMode === 'connect'}
         reconnectRadius={20}
         connectionRadius={24}
         deleteKeyCode={['Backspace', 'Delete']}
         multiSelectionKeyCode="Shift"
-        panOnDrag={interactionMode === 'pan'}
+        panOnDrag={interactionMode === 'pan' ? [0, 1] : [1]}
         selectionOnDrag={interactionMode === 'select'}
         panActivationKeyCode="Space"
         snapToGrid={true}
         snapGrid={[20, 20]}
         fitView
-        className={interactionMode === 'pan' ? 'bg-page cursor-grab active:cursor-grabbing' : 'bg-page'}
+        className={cn(
+          'bg-page',
+          interactionMode === 'pan' && 'cursor-grab active:cursor-grabbing',
+          interactionMode === 'connect' && 'rf-connect-mode cursor-crosshair',
+        )}
       >
         <Background variant={BackgroundVariant.Dots} color="var(--color-border-default)" gap={20} size={1} />
         <Controls className="!border-default !bg-card [&>button]:!border-default [&>button]:!bg-card [&>button]:!fill-text-primary" />