fix(frontend): Handle object values in FileInput component (#11948)

Fixes
[#11800](https://github.com/Significant-Gravitas/AutoGPT/issues/11800)

## Problem
The FileInput component crashed with `TypeError: e.startsWith is not a
function` when the value was an object (from external API) instead of a
string.

## Example Input Object
When using the external API
(`/external-api/v1/graphs/{id}/execute/{version}`), file inputs can be
passed as objects:

```json
{
  "node_input": {
    "input_image": {
      "name": "image.jpeg",
      "type": "image/jpeg",
      "size": 131147,
      "data": "/9j/4QAW..."
    }
  }
}
```

## Changes
- Updated `getFileLabelFromValue()` to handle object format: `{ name,
type, size, data }`
- Added type guards for string vs object values
- Graceful fallback for edge cases (null, undefined, empty object)

## Test cases verified
- Object with name: returns filename
- Object with type only: extracts and formats MIME type
- String data URI: parses correctly
- String file path: extracts extension
- Edge cases: returns "File" fallback

autogpt_platform/frontend/src/components/atoms/FileInput/FileInput.tsx

@@ -104,7 +104,31 @@ export function FileInput(props: Props) {
     return false;
   }
 
-  const getFileLabelFromValue = (val: string) => {
+  const getFileLabelFromValue = (val: unknown): string => {
+    // Handle object format from external API: { name, type, size, data }
+    if (val && typeof val === "object") {
+      const obj = val as Record<string, unknown>;
+      if (typeof obj.name === "string") {
+        return getFileLabel(
+          obj.name,
+          typeof obj.type === "string" ? obj.type : "",
+        );
+      }
+      if (typeof obj.type === "string") {
+        const mimeParts = obj.type.split("/");
+        if (mimeParts.length > 1) {
+          return `${mimeParts[1].toUpperCase()} file`;
+        }
+        return `${obj.type} file`;
+      }
+      return "File";
+    }
+
+    // Handle string values (data URIs or file paths)
+    if (typeof val !== "string") {
+      return "File";
+    }
+
     if (val.startsWith("data:")) {
       const matches = val.match(/^data:([^;]+);/);
       if (matches?.[1]) {