feat(10-11): teleport FolderRow three-dot menu to body with getBoundingClientRect positioning

- Add menuTriggerEl ref, menuStyle, and updateMenuPosition() using getBoundingClientRect
- Wrap three-dot menu in Teleport to body with data-test="folder-row-menu"
- toggleMenu() captures position before opening
- Add window scroll/resize listeners with cleanup in onUnmounted
- Update outside-click handler to also exclude teleported menu element
- All 4 UX-13 dropdown tests now pass; full test suite 208/208 green

frontend/src/components/folders/FolderRow.vue

@@ -36,6 +36,7 @@
     <!-- Three-dot menu -->
     <div class="relative shrink-0" @click.stop>
       <button
+        ref="menuTriggerEl"
         @click="toggleMenu"
         aria-label="Folder actions"
         class="p-1.5 rounded-md text-gray-400 hover:text-gray-600 hover:bg-gray-100 transition-colors min-h-[36px] min-w-[36px] flex items-center justify-center"
@@ -44,11 +45,17 @@
           <path d="M10 6a2 2 0 110-4 2 2 0 010 4zm0 6a2 2 0 110-4 2 2 0 010 4zm0 6a2 2 0 110-4 2 2 0 010 4z" />
         </svg>
       </button>
+    </div>
+  </div>
 
-      <!-- Dropdown menu -->
+  <!-- Teleported three-dot menu — avoids overflow:hidden clipping -->
+  <Teleport to="body">
     <div
       v-if="menuOpen"
-        class="absolute right-0 top-full mt-1 bg-white border border-gray-200 rounded-lg shadow-md py-1 min-w-[140px] z-10"
+      :style="menuStyle"
+      data-test="folder-row-menu"
+      class="fixed z-[9999] bg-white border border-gray-200 rounded-lg shadow-md py-1 min-w-[140px]"
+      @click.stop
     >
       <button
         @click="startRename"
@@ -63,8 +70,7 @@
         Delete folder
       </button>
     </div>
-    </div>
-  </div>
+  </Teleport>
 </template>
 
 <script setup>
@@ -90,6 +96,8 @@ const props = defineProps({
 })
 
 const menuOpen = ref(false)
+const menuTriggerEl = ref(null)
+const menuStyle = ref({})
 const renaming = ref(false)
 const renameValue = ref('')
 const renameError = ref('')
@@ -100,8 +108,33 @@ function handleNavigate() {
   if (props.onNavigate) props.onNavigate(props.folder.id)
 }
 
+function updateMenuPosition() {
+  if (!menuTriggerEl.value) return
+  const rect = menuTriggerEl.value.getBoundingClientRect()
+  const spaceBelow = window.innerHeight - rect.bottom
+  const dropH = 100 // approximate height of 2-item menu
+  if (spaceBelow >= dropH || spaceBelow > 60) {
+    menuStyle.value = {
+      top: `${rect.bottom + 4}px`,
+      left: `${Math.max(0, rect.right - 160)}px`,
+      minWidth: '140px',
+    }
+  } else {
+    menuStyle.value = {
+      bottom: `${window.innerHeight - rect.top + 4}px`,
+      left: `${Math.max(0, rect.right - 160)}px`,
+      minWidth: '140px',
+    }
+  }
+}
+
 function toggleMenu() {
-  menuOpen.value = !menuOpen.value
+  if (menuOpen.value) {
+    menuOpen.value = false
+  } else {
+    updateMenuPosition()
+    menuOpen.value = true
+  }
 }
 
 function closeMenu() {
@@ -146,16 +179,27 @@ function handleDelete() {
 
 // Close menu on outside click
 function handleOutsideClick(e) {
-  if (!e.target.closest('.relative')) {
+  if (
+    !e.target.closest('[data-test="folder-row-menu"]') &&
+    !e.target.closest('.relative')
+  ) {
     closeMenu()
   }
 }
 
+function onScroll() {
+  if (menuOpen.value) updateMenuPosition()
+}
+
 onMounted(() => {
   document.addEventListener('click', handleOutsideClick)
+  window.addEventListener('scroll', onScroll, true)
+  window.addEventListener('resize', onScroll)
 })
 
 onUnmounted(() => {
   document.removeEventListener('click', handleOutsideClick)
+  window.removeEventListener('scroll', onScroll, true)
+  window.removeEventListener('resize', onScroll)
 })
 </script>