fix: add explicit type annotations to extension callback parameters (#8966)

Fixes #8882

Adds explicit type annotations to all extension callback parameters
(`nodeCreated`, `beforeRegisterNodeDef`, `addCustomNodeDefs`) across 14
core extension files. While the types were already inferred from the
`ComfyExtension` interface, explicit annotations improve readability and
make the code self-documenting.

## Changes

- Annotate `node` parameter as `LGraphNode` in all `nodeCreated`
callbacks
- Annotate `nodeType` as `typeof LGraphNode` and `nodeData` as
`ComfyNodeDef` in all `beforeRegisterNodeDef` callbacks
- Annotate `defs` as `Record<string, ComfyNodeDef>` in
`addCustomNodeDefs`
- Add necessary type imports where missing

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8966-fix-add-explicit-type-annotations-to-extension-callback-parameters-30b6d73d36508125b074f509aa38145f)
by [Unito](https://www.unito.io)

src/extensions/core/widgetInputs.ts

@@ -16,7 +16,7 @@ import { assetService } from '@/platform/assets/services/assetService'
 import { createAssetWidget } from '@/platform/assets/utils/createAssetWidget'
 import { isCloud } from '@/platform/distribution/types'
 import { useSettingStore } from '@/platform/settings/settingStore'
-import type { InputSpec } from '@/schemas/nodeDefSchema'
+import type { ComfyNodeDef, InputSpec } from '@/schemas/nodeDefSchema'
 import { app } from '@/scripts/app'
 import {
   ComfyWidgets,
@@ -563,7 +563,10 @@ export function mergeIfValid(
 
 app.registerExtension({
   name: 'Comfy.WidgetInputs',
-  async beforeRegisterNodeDef(nodeType, _nodeData) {
+  async beforeRegisterNodeDef(
+    nodeType: typeof LGraphNode,
+    _nodeData: ComfyNodeDef
+  ) {
     // @ts-expect-error adding extra property
     nodeType.prototype.convertWidgetToInput = function (this: LGraphNode) {
       console.warn(