perf: code-split xterm bundle and gate terminal features for cloud (#8528)

## Summary

Code-splits the ~400KB xterm bundle and excludes terminal features from
cloud distribution where they are not needed.

### Changes

- **bottomPanelStore.ts**: Gate terminal tab registration behind
`__DISTRIBUTION__ !== 'cloud'` check with dynamic import, enabling
tree-shaking
- **keybindingService.ts**: Skip logs-terminal keybinding registration
for cloud distribution
- **vite.config.mts**: Add `vendor-xterm` code splitting group

### Bundle Impact

| Distribution | xterm in bundle | Terminal tabs |
|--------------|-----------------|---------------|
| cloud | ❌ No (~400KB saved) | None |
| localhost | ✅ Yes (vendor-xterm chunk) | Logs terminal |
| desktop | ✅ Yes (vendor-xterm chunk) | Logs + Command terminal |

### Verification Script

Run locally to verify xterm exclusion works correctly:

```bash
#!/bin/bash
set -e

echo "=== Verifying xterm bundle exclusion ==="
echo

# Clear Nx cache to ensure fresh builds
pnpm nx reset 2>/dev/null

# Build cloud distribution
echo "Building CLOUD distribution..."
rm -rf dist
DISTRIBUTION=cloud pnpm build --mode production 2>/dev/null

echo "Cloud build - checking for xterm:"
if grep -r "xterm" dist/assets/*.js >/dev/null 2>&1; then
  echo "  ❌ FAIL: xterm found in cloud bundle"
  grep -l "xterm" dist/assets/*.js | head -5
else
  echo "  ✅ PASS: xterm NOT in cloud bundle"
fi
echo

# Build localhost distribution
echo "Building LOCALHOST distribution..."
pnpm nx reset 2>/dev/null
rm -rf dist
DISTRIBUTION=localhost pnpm build --mode production 2>/dev/null

echo "Localhost build - checking for xterm:"
if grep -r "xterm" dist/assets/*.js >/dev/null 2>&1; then
  echo "  ✅ PASS: xterm found in localhost bundle"
  echo "  Files containing xterm:"
  grep -l "xterm" dist/assets/*.js | while read f; do
    size=$(wc -c < "$f")
    echo "    $(basename $f) ($(numfmt --to=iec $size))"
  done
else
  echo "  ❌ FAIL: xterm NOT in localhost bundle"
fi
echo

echo "=== Verification complete ==="
```

**Note**: Nx cache must be reset between builds with different
`DISTRIBUTION` values or it may return stale results.

## Test Plan

- [x] Quality gates pass (typecheck, lint, format, tests)
- [x] Cloud build verified: xterm NOT present
- [x] Localhost build verified: xterm present as vendor-xterm chunk

Fixes COM-14129

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8528-perf-code-split-xterm-bundle-and-gate-terminal-features-for-cloud-2fa6d73d365081a093ecc74ca7ce6e7c)
by [Unito](https://www.unito.io)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Refactor**
* Terminal tab declarations adjusted (no user-visible behavior change).
* Bottom panel tabs now load asynchronously; panel toggle falls back to
shortcuts when terminal tabs aren’t loaded.

* **Chores**
* Terminal tabs and related keybindings suppressed in cloud deployments.
  * Core commands wired to a new utility to support widget promotion.

* **Tests**
* E2E tests updated to handle async terminal-tab loading and minor test
cleanup.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: Alexander Brown <drjkl@comfy.org>

src/platform/keybindings/keybindingService.ts

@@ -1,3 +1,4 @@
+import { isCloud } from '@/platform/distribution/types'
 import { useSettingStore } from '@/platform/settings/settingStore'
 import { app } from '@/scripts/app'
 import { useCommandStore } from '@/stores/commandStore'
@@ -108,6 +109,12 @@ export function useKeybindingService() {
 
   function registerCoreKeybindings() {
     for (const keybinding of CORE_KEYBINDINGS) {
+      if (
+        isCloud &&
+        keybinding.commandId === 'Workspace.ToggleBottomPanelTab.logs-terminal'
+      ) {
+        continue
+      }
       keybindingStore.addDefaultKeybinding(new KeybindingImpl(keybinding))
     }
   }
@@ -119,6 +126,12 @@ export function useKeybindingService() {
     }
     const newBindings = settingStore.get('Comfy.Keybinding.NewBindings')
     for (const keybinding of newBindings) {
+      if (
+        isCloud &&
+        keybinding.commandId === 'Workspace.ToggleBottomPanelTab.logs-terminal'
+      ) {
+        continue
+      }
       keybindingStore.addUserKeybinding(new KeybindingImpl(keybinding))
     }
   }