refactor: merge keyframes/export/presets into one tabbed card

Right column now has two elements: preview canvas (shrink-0) and a
single glass card with Keyframes|Export|Presets tabs (flex-1).
Defaults to Keyframes tab. Removes the standalone timeline card and
the redundant embedded timeline in the mobile edit panel.

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

components/animate/AnimationEditor.tsx

@@ -12,7 +12,7 @@ import { cn } from '@/lib/utils/cn';
 import type { AnimationConfig, KeyframeProperties as KFProps, PreviewElement } from '@/types/animate';
 
 type MobileTab = 'edit' | 'preview';
-type RightTab = 'export' | 'presets';
+type RightTab = 'keyframes' | 'export' | 'presets';
 
 export function AnimationEditor() {
   const [config, setConfig] = useState<AnimationConfig>(DEFAULT_CONFIG);
@@ -21,7 +21,7 @@ export function AnimationEditor() {
   );
   const [previewElement, setPreviewElement] = useState<PreviewElement>('box');
   const [mobileTab, setMobileTab] = useState<MobileTab>('edit');
-  const [rightTab, setRightTab] = useState<RightTab>('export');
+  const [rightTab, setRightTab] = useState<RightTab>('keyframes');
 
   const selectedKeyframe = config.keyframes.find((k) => k.id === selectedId) ?? null;
 
@@ -108,33 +108,22 @@ export function AnimationEditor() {
 
               <div className="border-t border-border/25" />
 
-              {/* Timeline — embedded inside edit panel on mobile, hidden on desktop */}
-              <div className="lg:hidden">
-                <KeyframeTimeline {...timelineProps} embedded />
-              </div>
-              <div className="lg:hidden border-t border-border/25" />
-
               <KeyframeProperties keyframe={selectedKeyframe} onChange={updateKeyframeProps} />
             </div>
           </div>
         </div>
 
-        {/* Right: Preview + Timeline + Export/Presets */}
+        {/* Right: Preview + tabbed panel */}
         <div className={cn('lg:col-span-3 flex flex-col gap-3 overflow-hidden', mobileTab !== 'preview' && 'hidden lg:flex')}>
 
           {/* Preview canvas */}
           <AnimationPreview config={config} element={previewElement} onElementChange={setPreviewElement} />
 
-          {/* Timeline — standalone on desktop */}
-          <div className="hidden lg:block shrink-0">
-            <KeyframeTimeline {...timelineProps} />
-          </div>
-
-          {/* Export / Presets tab panel */}
+          {/* Keyframes / Export / Presets tab panel */}
           <div className="glass rounded-xl p-4 flex flex-col flex-1 min-h-0 overflow-hidden">
             {/* Tab switcher */}
             <div className="flex glass rounded-lg p-0.5 gap-0.5 mb-4 shrink-0">
-              {(['export', 'presets'] as RightTab[]).map((t) => (
+              {(['keyframes', 'export', 'presets'] as RightTab[]).map((t) => (
                 <button
                   key={t}
                   onClick={() => setRightTab(t)}
@@ -145,12 +134,13 @@ export function AnimationEditor() {
                       : 'text-muted-foreground hover:text-foreground'
                   )}
                 >
-                  {t === 'export' ? 'Export' : 'Presets'}
+                  {t === 'keyframes' ? 'Keyframes' : t === 'export' ? 'Export' : 'Presets'}
                 </button>
               ))}
             </div>
             {/* Content */}
             <div className="flex-1 min-h-0 overflow-y-auto scrollbar-thin scrollbar-thumb-primary/20 scrollbar-track-transparent pr-0.5">
+              {rightTab === 'keyframes' && <KeyframeTimeline {...timelineProps} embedded />}
               {rightTab === 'export' && <ExportPanel config={config} />}
               {rightTab === 'presets' && <PresetLibrary onSelect={loadPreset} />}
             </div>