fix(desktop): sidebar tab animation + memory deduplication

1. Fix sidebar tab switching: replace containerVariants (staggerChildren
   without motion children) with simple fade variants. The previous
   staggerChildren:0.05 caused the container to stay at opacity:0 when
   switching to CloneManager because non-motion children couldn't
   participate in stagger animation.

2. Fix memory deduplication: add content+agentId based dedup check
   in fallbackMemory.store(). Previously same content was stored 4x
   with different IDs. Now updates importance/accessCount instead.

desktop/src/components/Sidebar.tsx

@@ -6,7 +6,14 @@ import {
 import { ConversationList } from './ConversationList';
 import { CloneManager } from './CloneManager';
 import { useChatStore } from '../store/chatStore';
-import { containerVariants, defaultTransition } from '../lib/animations';
+import { defaultTransition } from '../lib/animations';
+
+// Simple fade variants for sidebar tab content (no staggerChildren)
+const sidebarTabVariants = {
+  hidden: { opacity: 0 },
+  visible: { opacity: 1, transition: { duration: 0.15 } },
+  exit: { opacity: 0, transition: { duration: 0.1 } },
+};
 
 export type MainViewType = 'chat' | 'automation' | 'skills';
 
@@ -109,7 +116,7 @@ export function Sidebar({
         <AnimatePresence mode="wait">
           <motion.div
             key={activeTab}
-            variants={containerVariants}
+            variants={sidebarTabVariants}
             initial="hidden"
             animate="visible"
             exit="exit"