Denial of service via unclamped nvs_read length

Out-of-bounds write in the settings NVS backend in Zephyr RTOS before 4.5.0 allows local users to crash the system via a crafted stored name entry. In settings_nvs_cache_match(), settings_nvs_load(), and settings_nvs_save(), the code uses the full length returned by nvs_read() as the index for a trailing NUL in a fixed 74-byte stack buffer, even when nvs_read() copied only a truncated prefix. Reachability is limited to actors that can persist an oversized setting name or otherwise alter the flash-backed settings partition before settings_load() or settings_save(); the practical result is a crash and limited stack corruption rather than reliable code execution.