[Bug]: Files with charset UTF-16 can't be uploaded for "file search"

[jogamned]

What happened?

Hello,

Files encoded in UTF-16 are causing a "Error processing file" when trying to upload them for RAG.

Here is an example of such a file

utf-16_ko.csv

Thank you

Version Information

We are using the version at this commit : dff4fcac00939cf5a9b2077eba4cadcfe47c72eb

Steps to Reproduce

Just upload a file in UTF16 for file search. No problem with code interpreter

What browsers are you seeing the problem on?

No response

Relevant log output

Logs : 
`
librechat-api-59dc4dcc65-vndwg librechat-api {"data":{"detail":"Error during file processing: Error loading ./uploads/6721f4dd44064b32c5269d84/utf-16_ko.csv"},"headers":{"content-length":"105","content-type":"application/json","date":"Wed, 02 Jul 2025 15:54:25 GMT","server":"uvicorn"},"level":"error","message":"Error uploading vectors The server responded with status 400: Request failed with status code 400","stack":"AxiosError: Request failed with status code 400\n    at settle (/app/node_modules/axios/dist/node/axios.cjs:2031:12)\n    at IncomingMessage.handleStreamEnd (/app/node_modules/axios/dist/node/axios.cjs:3148:11)\n    at IncomingMessage.emit (node:events:536:3...","status":400,"timestamp":"2025-07-02T15:54:26.272Z"}
librechat-api-59dc4dcc65-vndwg librechat-api {"level":"error","message":"[/files] Error processing file: Request failed with status code 400","stack":"Error: Request failed with status code 400\n    at uploadVectors (/app/api/server/services/Files/VectorDB/crud.js:113:11)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at async processAgentFileUpload (/app/api/server...","timestamp":"2025-07-02T15:54:26.273Z"}
`

Screenshots

No response

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