Fix: Error message: Use 'const' instead. (#13982)

### What problem does this PR solve?

Fix: Linter error message: Use 'const' instead.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Refactor**
* Updated variable declarations across form components, agent utilities,
memory management hooks, and data handling functions to enhance code
consistency and maintainability throughout the application codebase.

* **Style**
* Added ESLint suppressions to document intentional constant-condition
patterns in asynchronous event streaming operations.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

web/src/utils/file-util.ts

@@ -54,10 +54,10 @@ export const transformBase64ToFile = (
   dataUrl: string,
   filename: string = 'file',
 ) => {
-  let arr = dataUrl.split(','),
-    bstr = atob(arr[1]),
-    n = bstr.length,
-    u8arr = new Uint8Array(n);
+  const arr = dataUrl.split(','),
+    bstr = atob(arr[1]);
+  let n = bstr.length;
+  const u8arr = new Uint8Array(n);
 
   const mime = arr[0].match(/:(.*?);/);
   const mimeType = mime ? mime[1] : 'image/png';

web/src/utils/register-server.ts

@@ -17,7 +17,7 @@ const registerServer = <T extends string>(
   request: RequestMethod,
 ) => {
   const server: Service<T> = {} as Service<T>;
-  for (let key in opt) {
+  for (const key in opt) {
     server[key] = (params?: any, urlAppendix?: string) => {
       let url = opt[key].url;
       const requestOptions = opt[key];