Improve linear compatibility with Safari, run button metadata (#8107)

I downloaded the oldest webkit based browser I could find after reports
of display issues. The changes here cause some minor styling tweaks, but
should be more compatible overall. A quick list of fixed issues
- Center panel placeholder had incorrect aspect ratio
<img height="500" alt="image"
src="https://github.com/user-attachments/assets/b75e3c49-20d9-4d6e-bca4-95cc8a73f821"
/>
- Image previews had incorrect aspect ratio (But the other way around)
<img height="500" alt="image"
src="https://github.com/user-attachments/assets/b8ebc58e-2655-41f8-a3b4-70ba65940612"
/>
- On mobile, output groups would flex incorrectly, resulting in a large
gap between them
<img height="500" alt="image"
src="https://github.com/user-attachments/assets/ed7e8e43-c34e-4ffc-a3ee-126b1a2ef4e0"
/>



Also moves the run button trigger source to a new 'linear' type


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8107-Improve-linear-compatibility-with-Safari-run-button-metadata-2ea6d73d3650814e89cbc190b6ca8f87)
by [Unito](https://www.unito.io)

src/renderer/extensions/linearMode/LinearControls.vue

@@ -118,9 +118,6 @@ async function runButtonClick(e: Event) {
       ? 'Comfy.QueuePromptFront'
       : 'Comfy.QueuePrompt'
 
-    useTelemetry()?.trackUiButtonClicked({
-      button_id: props.mobile ? 'queue_run_linear_mobile' : 'queue_run_linear'
-    })
     if (batchCount.value > 1) {
       useTelemetry()?.trackUiButtonClicked({
         button_id: 'queue_run_multiple_batches_submitted'
@@ -129,7 +126,7 @@ async function runButtonClick(e: Event) {
     await commandStore.execute(commandId, {
       metadata: {
         subscribe_to_run: false,
-        trigger_source: 'button'
+        trigger_source: 'linear'
       }
     })
   } finally {