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/extensions/core/nodeTemplates.ts

@@ -32,9 +32,13 @@ import { GroupNodeConfig, GroupNodeHandler } from './groupNode'
 const id = 'Comfy.NodeTemplates'
 const file = 'comfy.templates.json'
 
+interface NodeTemplate {
+  name: string
+  data: string
+}
+
 class ManageTemplates extends ComfyDialog {
-  // @ts-expect-error fixme ts strict error
-  templates: any[]
+  templates: NodeTemplate[] = []
   draggedEl: HTMLElement | null
   saveVisualCue: number | null
   emptyImg: HTMLImageElement