Road to No explicit any Part 8 (Group 3): Improve type safety in Group 3 test mocks (#8304)

## Summary

- Eliminated all `as unknown as` type assertions from Group 3 test files
- Created reusable factory functions in `litegraphTestUtils.ts` for
better type safety
- Improved test mock composition using `Partial` types with single `as`
casts
- Fixed LGraphNode tests to use proper API methods instead of direct
property assignment

## Changes by Category

### New Factory Functions in `litegraphTestUtils.ts`

- `createMockLGraphNodeWithArrayBoundingRect()` - Creates LGraphNode
with proper boundingRect for position tests
- `createMockFileList()` - Creates mock FileList with proper structure
including `item()` method

### Test File Improvements

**Composables:**
- `useLoad3dDrag.test.ts` - Used `createMockFileList` factory
- `useLoad3dViewer.test.ts` - Created local `MockSceneManager` interface
with proper typing

**LiteGraph Tests:**
- `LGraphNode.test.ts` - Replaced direct `boundingRect` assignments with
`updateArea()` calls
- `LinkConnector.test.ts` - Improved mock composition with proper
Partial types
- `ToOutputRenderLink.test.ts` - Added `MockEvents` interface for
type-safe event mocking
- Updated integration and core tests to use new factory functions

**Extension Tests:**
- `contextMenuFilter.test.ts` - Updated menu factories to accept
`(IContextMenuValue | null)[]`

## Type Safety Improvements

- Zero `as unknown as` instances (was: multiple instances across 17
files)
- All mocks use proper `Partial<T>` composition with single `as T` casts
- Improved IntelliSense and type checking in test files
- Centralized mock creation reduces duplication and improves
maintainability

## Test Plan

- ✅ All TypeScript type checks pass
- ✅ ESLint passes with no new errors  
- ✅ Pre-commit hooks (format, lint, typecheck) all pass
- ✅ Knip unused export check passes
- ✅ No behavioral changes to actual tests (only type improvements)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8304-Road-to-No-explicit-any-Improve-type-safety-in-Group-3-test-mocks-2f36d73d365081ab841de96e5f01306d)
by [Unito](https://www.unito.io)

src/composables/useFeatureFlags.test.ts

@@ -30,8 +30,7 @@ describe('useFeatureFlags', () => {
     it('should access supportsPreviewMetadata', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
         (path, defaultValue) => {
-          if (path === ServerFeatureFlag.SUPPORTS_PREVIEW_METADATA)
-            return true as any
+          if (path === ServerFeatureFlag.SUPPORTS_PREVIEW_METADATA) return true
           return defaultValue
         }
       )
@@ -46,8 +45,7 @@ describe('useFeatureFlags', () => {
     it('should access maxUploadSize', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
         (path, defaultValue) => {
-          if (path === ServerFeatureFlag.MAX_UPLOAD_SIZE)
-            return 209715200 as any // 200MB
+          if (path === ServerFeatureFlag.MAX_UPLOAD_SIZE) return 209715200 // 200MB
           return defaultValue
         }
       )
@@ -62,7 +60,7 @@ describe('useFeatureFlags', () => {
     it('should access supportsManagerV4', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
         (path, defaultValue) => {
-          if (path === ServerFeatureFlag.MANAGER_SUPPORTS_V4) return true as any
+          if (path === ServerFeatureFlag.MANAGER_SUPPORTS_V4) return true
           return defaultValue
         }
       )
@@ -76,7 +74,7 @@ describe('useFeatureFlags', () => {
 
     it('should return undefined when features are not available and no default provided', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
-        (_path, defaultValue) => defaultValue as any
+        (_path, defaultValue) => defaultValue
       )
 
       const { flags } = useFeatureFlags()
@@ -90,7 +88,7 @@ describe('useFeatureFlags', () => {
     it('should create reactive computed for custom feature flags', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
         (path, defaultValue) => {
-          if (path === 'custom.feature') return 'custom-value' as any
+          if (path === 'custom.feature') return 'custom-value'
           return defaultValue
         }
       )
@@ -108,7 +106,7 @@ describe('useFeatureFlags', () => {
     it('should handle nested paths', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
         (path, defaultValue) => {
-          if (path === 'extension.custom.nested.feature') return true as any
+          if (path === 'extension.custom.nested.feature') return true
           return defaultValue
         }
       )
@@ -122,8 +120,7 @@ describe('useFeatureFlags', () => {
     it('should work with ServerFeatureFlag enum', () => {
       vi.mocked(api.getServerFeature).mockImplementation(
         (path, defaultValue) => {
-          if (path === ServerFeatureFlag.MAX_UPLOAD_SIZE)
-            return 104857600 as any
+          if (path === ServerFeatureFlag.MAX_UPLOAD_SIZE) return 104857600
           return defaultValue
         }
       )