Linear: progressbar, tooltips, and output fixes (#8250)

- Fixes only the first output being displayed in linear mode after the
jobs migration
- Fixes selected output no longer scrolling into view in history
- Adds a progress bar indicator on running job
<img width="113" height="102" alt="image"
src="https://github.com/user-attachments/assets/ca684dbe-12c8-44aa-98f0-2985c0159156"
/>
- Moves linear toggle button to v-tooltip
- Fixes placeholder sometimes continuing to display after a new output.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8250-Linear-progressbar-tooltips-and-output-fixes-2f06d73d365081ca9fa3ebf0e2516487)
by [Unito](https://www.unito.io)

src/renderer/extensions/linearMode/LinearPreview.vue

@@ -159,7 +159,7 @@ async function rerun(e: Event) {
   <VideoPreview
     v-else-if="getMediaType(selectedOutput) === 'video'"
     :src="selectedOutput!.url"
-    class="object-contain flex-1 md:contain-size"
+    class="object-contain flex-1 md:contain-size md:p-3"
   />
   <audio
     v-else-if="getMediaType(selectedOutput) === 'audio'"