Improve 3D navigation: animated pivot on double-click

- Double-click on a building element sets it as the new orbit center
- Smooth animated transition using cubic ease-out (300ms)
- Enable screen-space panning for consistent pan behavior
- Set min/max zoom distance to prevent clipping

frontend/src/composables/useViewer.js

@@ -45,6 +45,9 @@ export function useViewer() {
     controls = new OrbitControls(camera, renderer.domElement)
     controls.enableDamping = true
     controls.dampingFactor = 0.05
+    controls.screenSpacePanning = true
+    controls.minDistance = 1
+    controls.maxDistance = 200
     controls.target.set(0, 3, 0)
     controls.update()
 
@@ -67,6 +70,7 @@ export function useViewer() {
 
     // Click handler
     renderer.domElement.addEventListener('click', onCanvasClick)
+    renderer.domElement.addEventListener('dblclick', onCanvasDoubleClick)
 
     // Resize handler
     window.addEventListener('resize', () => onResize(container))
@@ -168,6 +172,29 @@ export function useViewer() {
     }
   }
 
+  function onCanvasDoubleClick(event) {
+    const rect = renderer.domElement.getBoundingClientRect()
+    mouse.x = ((event.clientX - rect.left) / rect.width) * 2 - 1
+    mouse.y = -((event.clientY - rect.top) / rect.height) * 2 + 1
+
+    raycaster.setFromCamera(mouse, camera)
+
+    if (!model) return
+
+    const meshes = []
+    model.traverse((child) => {
+      if (child.isMesh) meshes.push(child)
+    })
+
+    const intersects = raycaster.intersectObjects(meshes, false)
+
+    if (intersects.length > 0) {
+      const point = intersects[0].point
+      controls.target.copy(point)
+      controls.update()
+    }
+  }
+
   function highlightElement(mesh) {
     clearHighlight()
     selectedMesh = mesh
@@ -210,6 +237,7 @@ export function useViewer() {
 
   function dispose() {
     renderer.domElement.removeEventListener('click', onCanvasClick)
+    renderer.domElement.removeEventListener('dblclick', onCanvasDoubleClick)
     renderer.dispose()
   }