feat: add per-video reprocess button to status bar

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

src/lib/components/StatusBar.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
   import { getVersion } from '@tauri-apps/api/app';
-  import { session, upgradePreview } from '$lib/stores/videoSession.svelte';
+  import { session, upgradePreview, reprocessCurrentVideo } from '$lib/stores/videoSession.svelte';
 
   let { onOpenAbout }: { onOpenAbout?: () => void } = $props();
 
@@ -25,6 +25,23 @@
   let isPreviewComplete = $derived(session.previewStatus === 'complete');
   let isExportDownloading = $derived(session.exportStatus === 'downloading');
   let isExportComplete = $derived(session.exportStatus === 'complete');
+
+  let canReprocess = $derived(
+    session.status === 'ready' &&
+      session.processingStep === 'done' &&
+      session.activeVideoPath !== null
+  );
+
+  let reprocessing = $state(false);
+
+  async function handleReprocess() {
+    reprocessing = true;
+    try {
+      await reprocessCurrentVideo();
+    } finally {
+      reprocessing = false;
+    }
+  }
 </script>
 
 <div class="status-bar">
@@ -53,6 +70,16 @@
   {:else}
     <span class="status-text">Ready</span>
   {/if}
+  {#if canReprocess && !isPreviewDownloading}
+    <button
+      class="reprocess-btn"
+      onclick={handleReprocess}
+      disabled={reprocessing}
+      title="Reprocess video (re-extract waveform, thumbnails, keyframes)"
+    >
+      {reprocessing ? '⏳' : '↻'}
+    </button>
+  {/if}
   {#if appVersion}
     <button class="version-btn" onclick={() => onOpenAbout?.()} title="About GUI Video Clipper">
       v{appVersion}
@@ -108,6 +135,27 @@
     color: var(--bg-primary, #1e1e2e);
   }
 
+  .reprocess-btn {
+    background: none;
+    border: 1px solid var(--border);
+    color: var(--text-secondary);
+    font-size: 14px;
+    padding: 2px 6px;
+    border-radius: 3px;
+    cursor: pointer;
+    line-height: 1;
+  }
+
+  .reprocess-btn:hover {
+    background: var(--bg-secondary);
+    color: var(--text-primary);
+  }
+
+  .reprocess-btn:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+  }
+
   .version-btn {
     margin-left: auto;
     background: none;