docs: Update ChangeLog and README.md for 12.0.0
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+2026-04-25 Mintsuki <mintsuki@protonmail.com>
+
+ *** Release 12.0.0 ***
+
+ Noteworthy changes compared to the previous release, 11.4.1:
+
+ Breaking changes:
+ - Re-introduce hash verification enforcement for files loaded under
+ UEFI Secure Boot (originally shipped in 11.2.0 and reverted in 11.2.1
+ pending the next major version bump). When Secure Boot is active,
+ Limine now requires an enrolled config checksum, BLAKE2B hashes on
+ all loaded file paths (with EFI chainloads exempted, as they rely on
+ firmware-side Secure Boot verification, and wallpaper and font files
+ silently skipped on a missing hash), unconditionally disables the
+ config editor, and forces `hash_mismatch_panic` to `yes`.
+ - The `interface_branding_colour` and `interface_help_colour` config
+ options now take an `RRGGBB` hexadecimal value instead of a 0-7
+ colour index. A new `interface_help_colour_bright` option has been
+ added to control the brighter accent colour used for the auto-boot
+ countdown digit.
+
+ New features:
+ - Re-introduce transparent gzip decompression for files, using a port
+ of embeddable pdgzip (CC0) by Kamila Szewczyk that provides
+ significantly better decode performance than the previous tinf-based
+ implementation.
+ - Major overhaul of the boot menu interface, including consistent
+ left-biased centering of all UI elements, ellipsis truncation of long
+ branding strings, shortened countdown text, and the removal of entry
+ name length limits.
+
+ Bug fixes:
+ - Fix NULL dereference in `gterm_init` cached path.
+ - Fix NULL dereference in the menu when `default_entry` is out of range
+ with `timeout=0`.
+ - Add a trailing fence after the `cbo.flush` loop in the RISC-V Zicbom
+ framebuffer flush path.
+ - Miscellaneous bug fixes.
+
+ Miscellaneous:
+ - Replace upstream `stb_image` with a hardened version.
+ - Bring back hand-written assembly versions of the x86-64 and IA-32
+ `mem*()` routines to mitigate performance regressions versus the C
+ implementations.
+ - Updated the Flanterm library to 3.1.1.
+ - Ship binary releases as tarballs in release assets, replacing the
+ previous separate git branch.
+
2026-04-20 Mintsuki <mintsuki@protonmail.com>
*** Release 11.4.1 ***
