bug: Mentors page language filter is ignored (sends 'language' instead of 'languages')

[yingliu-data]

Bug Report

The mentors-page language filter is silently ignored because the frontend sends the wrong query-param name.

• src/pages/api/mentors.ts:38-43 forwards the filter as language, but the backend binds @RequestParam List<CodeLanguage> languages (wcc-backend/.../controller/MentorshipPagesController.java:99).
• Same file: mentorshipTypes is appended twice (lines 26-31 and 44-48), sending a duplicated param.

Reproduction

On src/pages/mentorship/mentors.tsx (line ~98) the user selects a language → request goes out as ?language=JAVA → the backend never binds it → the full, unfiltered mentor list renders as though the filter applied.

Severity

Medium

Potential Risk

• The language filter appears functional but does nothing, misleading users.

Suggested Fix

• Send the param as languages (matching the backend), supporting repeated/CSV values as the backend expects.
• Remove the duplicate mentorshipTypes append.
• Add a test asserting the outgoing request uses languages.