EVerest has off-by-one stack buffer overflow in IsoMux certificate filename parsing

EVerest is an EV charging software stack. Prior to version 2026.02.0, an off-by-one check in IsoMux certificate filename handling causes a stack-based buffer overflow when a filename length equals `MAX_FILE_NAME_LENGTH` (100). A crafted filename in the certificate directory can overflow `file_names[idx]`, corrupting stack state and enabling potential code execution. Version 2026.02.0 contains a patch.