fix: address final review findings (clip reset, codecs, paths, timeline)

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

src/lib/components/Timeline.svelte

@@ -31,7 +31,9 @@
 
   $effect(() => {
     if (session.duration > 0) {
+      timelineState.visibleStart = 0;
       timelineState.visibleEnd = session.duration;
+      timelineState.zoom = 1;
     }
   });
 

src/lib/stores/videoSession.svelte.ts

@@ -8,6 +8,7 @@ import {
   extractWaveform,
 } from '$lib/bindings/mediaAnalysis';
 import { clearThumbnailCache } from '$lib/timeline/thumbnailRenderer';
+import { clearAll as clearAllClips } from '$lib/stores/clips.svelte';
 
 export type SessionStatus = 'idle' | 'resolving' | 'ready' | 'error';
 export type DownloadStatus = 'idle' | 'downloading' | 'complete' | 'failed';
@@ -32,6 +33,7 @@ export const session = $state({
 });
 
 export function setMetadata(meta: VideoMetadata) {
+  clearAllClips();
   session.url = meta.url;
   session.title = meta.title;
   session.duration = meta.duration;
@@ -73,6 +75,7 @@ export function setError(msg: string) {
 }
 
 export function setResolving() {
+  clearAllClips();
   clearMediaFields();
   session.status = 'resolving';
   session.error = null;

src/lib/timeline/interactions.ts

@@ -17,6 +17,13 @@ export function computeZoom(
   duration: number
 ): { visibleStart: number; visibleEnd: number; zoom: number } {
   const currentRange = state.visibleEnd - state.visibleStart;
+  if (currentRange <= 0) {
+    return {
+      visibleStart: state.visibleStart,
+      visibleEnd: state.visibleEnd,
+      zoom: state.zoom,
+    };
+  }
   const newRange = currentRange / factor;
   const clampedRange = Math.max(MIN_VISIBLE_RANGE, Math.min(newRange, duration));
 

src/lib/transport/playback.ts

@@ -44,6 +44,13 @@ export function jumpKeyframe(direction: 1 | -1) {
   }
 }
 
+export function resetShuttleRate() {
+  const videoEl = document.querySelector('video');
+  if (videoEl) {
+    videoEl.playbackRate = 1;
+  }
+}
+
 export function adjustShuttle(dir: 1 | -1, shuttleRate: number): number {
   const videoEl = document.querySelector('video');
   if (!videoEl) return shuttleRate;