fix: show empty timeline lanes when no video is loaded

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/components/Timeline.svelte

@@ -83,7 +83,8 @@
       clipStore.selectedClipId,
       clipStore.pendingInPoint,
       waveformData,
-      session.thumbnailSpritesheets
+      session.thumbnailSpritesheets,
+      session.status === 'ready'
     );
     ctx.restore();
   }

src/lib/timeline/renderer.ts

@@ -37,7 +37,8 @@ export function drawTimeline(
   selectedClipId: string | null = null,
   pendingInPoint: number | null = null,
   waveform: WaveformData = { tiers: null },
-  thumbnailSpritesheets: ThumbnailSpritesheet[] = []
+  thumbnailSpritesheets: ThumbnailSpritesheet[] = [],
+  hasVideo: boolean = false
 ): void {
   const { width, height } = state;
   ctx.clearRect(0, 0, width, height);
@@ -50,13 +51,13 @@ export function drawTimeline(
   if (thumbnailSpritesheets.length > 0) {
     drawThumbnails(ctx, state, thumbnailSpritesheets, duration, 0, THUMB_LANE_HEIGHT);
   } else {
-    drawPlaceholderLane(ctx, state, 0, THUMB_LANE_HEIGHT, 'Thumbnails');
+    drawPlaceholderLane(ctx, state, 0, THUMB_LANE_HEIGHT, 'Thumbnails', hasVideo);
   }
 
   if (waveform.tiers) {
     drawWaveform(ctx, state, waveform, duration, THUMB_LANE_HEIGHT, WAVEFORM_LANE_HEIGHT);
   } else {
-    drawPlaceholderLane(ctx, state, THUMB_LANE_HEIGHT, WAVEFORM_LANE_HEIGHT, 'Waveform');
+    drawPlaceholderLane(ctx, state, THUMB_LANE_HEIGHT, WAVEFORM_LANE_HEIGHT, 'Waveform', hasVideo);
   }
 
   drawClips(ctx, state, clips, selectedClipId, pendingInPoint);
@@ -114,17 +115,20 @@ function drawPlaceholderLane(
   state: TimelineState,
   y: number,
   height: number,
-  label: string
+  label: string,
+  showLabel: boolean
 ): void {
   ctx.fillStyle = '#2a2a3e';
   ctx.fillRect(0, y, state.width, height);
   ctx.strokeStyle = '#353550';
   ctx.strokeRect(0, y, state.width, height);
+  if (showLabel) {
     ctx.fillStyle = '#6c7086';
     ctx.font = '11px -apple-system, sans-serif';
     ctx.textAlign = 'center';
     ctx.fillText(`Generating ${label}…`, state.width / 2, y + height / 2 + 4);
   }
+}
 
 export function drawPlayhead(
   ctx: CanvasRenderingContext2D,