feat: replace Remotion with custom Bradly Engine (Phases 1-3)

- Phase 1: Custom animation engine (interpolate, spring, Easing)
- Phase 2: Custom composition components (AbsoluteFill, Sequence, Img, Video, Audio)
- Phase 3: BradlyPlayer with rAF frame loop, imperative API, controls

Migrated 24 files from remotion/@remotion/player imports to src/engine/.
All type errors from migration resolved. Pre-existing errors remain unchanged.

src/components/express/ExpressEditor.tsx

@@ -1,6 +1,6 @@
 import React, { useState, useMemo, useCallback, useRef } from 'react';
 import { ArrowLeft, Zap, Wrench, Download, ChevronRight, Play, Pause, RotateCcw } from 'lucide-react';
-import { Player, PlayerRef } from '@remotion/player';
+import { BradlyPlayer, BradlyPlayerRef } from '../../engine/player';
 import { ExpressTemplate, DesignMD, TimelineElement, TimelineLayer, CompanyProfile } from '../../types';
 import { BrandComposition } from '../BrandComposition';
 import { ExpressTemplateGallery } from './ExpressTemplateGallery';
@@ -42,7 +42,7 @@ export const ExpressEditor: React.FC<ExpressEditorProps> = ({
   const [showLogo, setShowLogo] = useState(true);
   const [overlayOpacity, setOverlayOpacity] = useState(0);
 
-  const playerRef = useRef<PlayerRef>(null);
+  const playerRef = useRef<BradlyPlayerRef>(null);
 
   const handleSelectTemplate = useCallback((template: ExpressTemplate) => {
     setSelectedTemplate(template);
@@ -208,7 +208,7 @@ export const ExpressEditor: React.FC<ExpressEditorProps> = ({
                   maxHeight: 'calc(100% - 80px)',
                 }}
               >
-                <Player
+                <BradlyPlayer
                   ref={playerRef}
                   component={BrandComposition}
                   inputProps={{