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/composables/queue/useQueueNotificationBanners.test.ts

@@ -3,7 +3,6 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { nextTick, reactive } from 'vue'
 
 import { useQueueNotificationBanners } from '@/composables/queue/useQueueNotificationBanners'
-import { api } from '@/scripts/api'
 import { useExecutionStore } from '@/stores/executionStore'
 import { useQueueStore } from '@/stores/queueStore'
 
@@ -135,7 +134,7 @@ describe(useQueueNotificationBanners, () => {
     const { wrapper, composable } = mountComposable()
 
     try {
-      ;(api as unknown as EventTarget).dispatchEvent(
+      mockApi.dispatchEvent(
         new CustomEvent('promptQueued', { detail: { batchCount: 4 } })
       )
       await nextTick()
@@ -157,7 +156,7 @@ describe(useQueueNotificationBanners, () => {
     const { wrapper, composable } = mountComposable()
 
     try {
-      ;(api as unknown as EventTarget).dispatchEvent(
+      mockApi.dispatchEvent(
         new CustomEvent('promptQueueing', {
           detail: { requestId: 1, batchCount: 2 }
         })
@@ -170,7 +169,7 @@ describe(useQueueNotificationBanners, () => {
         requestId: 1
       })
 
-      ;(api as unknown as EventTarget).dispatchEvent(
+      mockApi.dispatchEvent(
         new CustomEvent('promptQueued', {
           detail: { requestId: 1, batchCount: 2 }
         })
@@ -191,7 +190,7 @@ describe(useQueueNotificationBanners, () => {
     const { wrapper, composable } = mountComposable()
 
     try {
-      ;(api as unknown as EventTarget).dispatchEvent(
+      mockApi.dispatchEvent(
         new CustomEvent('promptQueued', { detail: { batchCount: 0 } })
       )
       await nextTick()