fix: replace as-unknown-as casts with safer patterns (#9107)

## Summary

- Replace 83 `as unknown as` double casts with safer alternatives across
33 files
- Use `as Partial<X> as X` pattern where TypeScript allows it
- Create/reuse factory functions from `litegraphTestUtils.ts` for mock
objects
- Widen `getWorkflowDataFromFile` return type to include `ComfyMetadata`
directly
- Reduce total `as unknown as` count from ~153 to 71

The remaining 71 occurrences are genuinely necessary due to cross-schema
casts, generic variance, missing index signatures, Float64Array-to-tuple
conversions, and DOM type incompatibilities.

## Test plan

- [x] `pnpm typecheck` passes
- [x] `pnpm lint` passes
- [x] All affected unit tests pass

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9107-fix-replace-as-unknown-as-casts-with-safer-patterns-3106d73d3650815cb5bcd613ad635bd7)
by [Unito](https://www.unito.io)

src/stores/workspace/searchBoxStore.test.ts

@@ -20,17 +20,17 @@ vi.mock('@/platform/settings/settingStore', () => ({
 }))
 
 function createMockPopover(): InstanceType<typeof NodeSearchBoxPopover> {
-  return { showSearchBox: vi.fn() } satisfies Partial<
+  return { showSearchBox: vi.fn() } as Partial<
     InstanceType<typeof NodeSearchBoxPopover>
-  > as unknown as InstanceType<typeof NodeSearchBoxPopover>
+  > as InstanceType<typeof NodeSearchBoxPopover>
 }
 
 function createMockSettingStore(): ReturnType<typeof useSettingStore> {
   return {
     get: vi.fn()
-  } satisfies Partial<
-    ReturnType<typeof useSettingStore>
-  > as unknown as ReturnType<typeof useSettingStore>
+  } as Partial<ReturnType<typeof useSettingStore>> as ReturnType<
+    typeof useSettingStore
+  >
 }
 
 describe('useSearchBoxStore', () => {