📦 chore: Bump Express.js to v5 (#10671)

* chore: update express to version 5.1.0 in package.json

* chore: update express-rate-limit to version 8.2.1 in package.json and package-lock.json

* fix: Enhance server startup error handling in experimental and index files

* Added error handling for server startup in both experimental.js and index.js to log errors and exit the process if the server fails to start.
* Updated comments in openidStrategy.js to clarify the purpose of the CustomOpenIDStrategy class and its relation to Express version changes.

* chore: Implement rate limiting for all POST routes excluding /speech, required for express v5

* Added middleware to apply IP and user rate limiters to all POST requests, ensuring that the /speech route remains unaffected.
* Enhanced code clarity with comments explaining the new rate limiting logic.

* chore: Enable writable req.query for mongoSanitize compatibility in Express 5

* chore: Ensure req.body exists in multiple middleware and route files for Express 5 compatibility

api/server/middleware/buildEndpointOption.js

@@ -89,6 +89,7 @@ async function buildEndpointOption(req, res, next) {
       : buildFunction[endpointType ?? endpoint];
 
     // TODO: use object params
+    req.body = req.body || {}; // Express 5: ensure req.body exists
     req.body.endpointOption = await builder(endpoint, parsedBody, endpointType);
 
     if (req.body.files && !isAgents) {