fix(auth): handle all PyJWT errors gracefully and enforce link code status checks

repositories/link_codes.py

@@ -32,3 +32,10 @@ async def get_link_code_by_code(session: AsyncSession, code: str) -> LinkCode |
     r = await session.execute(stmt)
 
     return r.scalar_one_or_none()
+
+
+async def use_link_code(session: AsyncSession, code: LinkCode) -> LinkCode:
+    code.status = LinkCodeStatus.USED
+    await session.commit()
+
+    return code