7.2.9-200.secureblue.1

What's Changed

• feat: enable CONFIG_ZERO_CALL_USED_REGS by @RoyalOughtness in #37
• feat: add additional low-risk hardening by @RoyalOughtness in #38

Full Changelog: 7.2.8-200.secureblue.3...7.2.9-200.secureblue.1