test: migrate as unknown as to @total-typescript/shoehorn (#10761)

*PR Created by the Glary-Bot Agent*

---

## Summary

- Replace all `as unknown as Type` assertions in 59 unit test files with
type-safe `@total-typescript/shoehorn` functions
- Use `fromPartial<Type>()` for partial mock objects where deep-partial
type-checks (21 files)
- Use `fromAny<Type>()` for fundamentally incompatible types: null,
undefined, primitives, variables, class expressions, and mocks with
test-specific extra properties that `PartialDeepObject` rejects
(remaining files)
- All explicit type parameters preserved so TypeScript return types are
correct
- Browser test `.spec.ts` files excluded (shoehorn unavailable in
`page.evaluate` browser context)

## Verification

- `pnpm typecheck` ✅
- `pnpm lint` ✅
- `pnpm format` ✅
- Pre-commit hooks passed (format + oxlint + eslint + typecheck)
- Migrated test files verified passing (ran representative subset)
- No test behavior changes — only type assertion syntax changed
- No UI changes — screenshots not applicable

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10761-test-migrate-as-unknown-as-to-total-typescript-shoehorn-3336d73d365081f6b8adc44db5dcc380)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Glary-Bot <glary-bot@users.noreply.github.com>
Co-authored-by: Amp <amp@ampcode.com>

src/renderer/extensions/linearMode/flattenNodeOutput.test.ts

@@ -1,3 +1,4 @@
+import { fromPartial } from '@total-typescript/shoehorn'
 import { describe, expect, it } from 'vitest'
 
 import { flattenNodeOutput } from '@/renderer/extensions/linearMode/flattenNodeOutput'
@@ -84,10 +85,12 @@ describe(flattenNodeOutput, () => {
   })
 
   it('flattens non-standard output keys with ResultItem-like values', () => {
-    const output = makeOutput({
-      a_images: [{ filename: 'before.png', subfolder: '', type: 'output' }],
-      b_images: [{ filename: 'after.png', subfolder: '', type: 'output' }]
-    } as unknown as Partial<NodeExecutionOutput>)
+    const output = makeOutput(
+      fromPartial<NodeExecutionOutput>({
+        a_images: [{ filename: 'before.png', subfolder: '', type: 'output' }],
+        b_images: [{ filename: 'after.png', subfolder: '', type: 'output' }]
+      })
+    )
 
     const result = flattenNodeOutput(['10', output])
 
@@ -109,10 +112,10 @@ describe(flattenNodeOutput, () => {
   })
 
   it('excludes non-ResultItem array items', () => {
-    const output = {
+    const output = fromPartial<NodeExecutionOutput>({
       images: [{ filename: 'img.png', subfolder: '', type: 'output' }],
       custom_data: [{ randomKey: 123 }]
-    } as unknown as NodeExecutionOutput
+    })
 
     const result = flattenNodeOutput(['1', output])
 
@@ -121,12 +124,12 @@ describe(flattenNodeOutput, () => {
   })
 
   it('accepts items with filename but no subfolder', () => {
-    const output = {
+    const output = fromPartial<NodeExecutionOutput>({
       images: [
         { filename: 'valid.png', subfolder: '', type: 'output' },
         { filename: 'no-subfolder.png' }
       ]
-    } as unknown as NodeExecutionOutput
+    })
 
     const result = flattenNodeOutput(['1', output])
 
@@ -137,12 +140,12 @@ describe(flattenNodeOutput, () => {
   })
 
   it('excludes items missing filename', () => {
-    const output = {
+    const output = fromPartial<NodeExecutionOutput>({
       images: [
         { filename: 'valid.png', subfolder: '', type: 'output' },
         { subfolder: '', type: 'output' }
       ]
-    } as unknown as NodeExecutionOutput
+    })
 
     const result = flattenNodeOutput(['1', output])