feat(floating-ai): step 7 — implement morph animation (FLIP)

Add FLIP animation so the floating chat visually morphs into a newly-created
TaskRow when the AI creates a task. Uses Framer Motion's shared layoutId
across FloatingChat and TaskRow, with LayoutGroup wrapping the app shell.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/renderer/components/layout/AppShell.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect, useRef, useCallback } from 'react';
 import { Link, useRouterState } from '@tanstack/react-router';
-import { motion, useMotionValue, useSpring } from 'framer-motion';
+import { LayoutGroup, motion, useMotionValue, useSpring } from 'framer-motion';
 import {
   House,
   ChartGantt,
@@ -221,7 +221,7 @@ function AppShellInner({ children }: AppShellProps) {
   }, [openCurtain, closeCurtain]);
 
   return (
-    <>
+    <LayoutGroup>
     <SidebarProvider open={open} onOpenChange={handleOpenChange}>
       <AppSidebar
         currentPath={currentPath}
@@ -314,7 +314,7 @@ function AppShellInner({ children }: AppShellProps) {
         </DialogFooter>
       </DialogContent>
     </Dialog>
-    </>
+    </LayoutGroup>
   );
 }