feat: add setMany to settingStore for batch setting updates (#8767)

## Summary
- Adds `setMany()` method to `settingStore` for updating multiple
settings in a single API call via the existing `storeSettings` endpoint
- Extracts shared setting-apply logic (`applySettingLocally`) to reduce
duplication between `set()` and `setMany()`
- Migrates all call sites where multiple settings were updated
sequentially to use `setMany()`

## Call sites updated
- `releaseStore.ts` — `handleSkipRelease`, `handleShowChangelog`,
`handleWhatsNewSeen` (3 settings each)
- `keybindingService.ts` — `persistUserKeybindings` (2 settings)
- `coreSettings.ts` — `NavigationMode.onChange` (2 settings)

## Test plan
- [x] Unit tests for `setMany` (batch update, skip unchanged, no-op when
unchanged)
- [x] Updated `releaseStore.test.ts` assertions to verify `setMany`
usage
- [x] Updated `useCoreCommands.test.ts` mock to include `setMany`
- [x] All existing tests pass
- [x] `pnpm typecheck`, `pnpm lint`, `pnpm format` pass

Fixes #1079

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8767-feat-add-setMany-to-settingStore-for-batch-setting-updates-3036d73d36508161b8b6d298e1be1b7a)
by [Unito](https://www.unito.io)

src/platform/settings/constants/coreSettings.ts

@@ -170,13 +170,15 @@ export const CORE_SETTINGS: SettingParams[] = [
       const settingStore = useSettingStore()
 
       if (newValue === 'standard') {
-        // Update related settings to match standard mode - select + panning
-        await settingStore.set('Comfy.Canvas.LeftMouseClickBehavior', 'select')
-        await settingStore.set('Comfy.Canvas.MouseWheelScroll', 'panning')
+        await settingStore.setMany({
+          'Comfy.Canvas.LeftMouseClickBehavior': 'select',
+          'Comfy.Canvas.MouseWheelScroll': 'panning'
+        })
       } else if (newValue === 'legacy') {
-        // Update related settings to match legacy mode - panning + zoom
-        await settingStore.set('Comfy.Canvas.LeftMouseClickBehavior', 'panning')
-        await settingStore.set('Comfy.Canvas.MouseWheelScroll', 'zoom')
+        await settingStore.setMany({
+          'Comfy.Canvas.LeftMouseClickBehavior': 'panning',
+          'Comfy.Canvas.MouseWheelScroll': 'zoom'
+        })
       }
     }
   },