feat: Add image upload support to ChatOpenRouter node (#5471)

* feat: Add image upload support to ChatOpenRouter node

- Create FlowiseChatOpenRouter wrapper class implementing IVisionChatModal
- Add allowImageUploads and imageResolution input fields
- Support multimodal image inputs for OpenRouter models
- Follows same pattern as ChatOpenAI implementation

Resolves #5143

* lint fix

---------

Co-authored-by: Henry <hzj94@hotmail.com>

packages/components/nodes/chatmodels/ChatOpenRouter/FlowiseChatOpenRouter.ts

@@ -0,0 +1,29 @@
+import { ChatOpenAI as LangchainChatOpenAI, ChatOpenAIFields } from '@langchain/openai'
+import { IMultiModalOption, IVisionChatModal } from '../../../src'
+
+export class ChatOpenRouter extends LangchainChatOpenAI implements IVisionChatModal {
+    configuredModel: string
+    configuredMaxToken?: number
+    multiModalOption: IMultiModalOption
+    id: string
+
+    constructor(id: string, fields?: ChatOpenAIFields) {
+        super(fields)
+        this.id = id
+        this.configuredModel = fields?.modelName ?? ''
+        this.configuredMaxToken = fields?.maxTokens
+    }
+
+    revertToOriginalModel(): void {
+        this.model = this.configuredModel
+        this.maxTokens = this.configuredMaxToken
+    }
+
+    setMultiModalOption(multiModalOption: IMultiModalOption): void {
+        this.multiModalOption = multiModalOption
+    }
+
+    setVisionModel(): void {
+        // pass - OpenRouter models don't need model switching
+    }
+}