docs: CHANGELOG: Steamify ISO 1.0.0 (unreleased), with the systemd-boot boot entry fix

CHANGELOG.md

@@ -1,3 +1,38 @@
+# Steamify ISO 1.0.0 (unreleased)
+CachyOS's desktop ISO with Steamify built in: install CachyOS and turn the PC into a Steam Machine in
+one go. Based on CachyOS 26.08 (its own notes follow below).
+
+**Features:**
+
+* **ISO:** called `steamify-cachyos-<date>-x86_64.iso`; CachyOS Hello installs it like CachyOS's own
+  release (the build date is kept in `/etc/steammachine-iso-build`)
+* **Installer (CachyOS - Steamify Installer):**
+  * A Steamify page after the packages page: which Steam Machine parts to set up (rows from
+    `steamify.sh --defaults --list`, the newest Steamify fetched before Calamares starts) and where
+    the PC starts (gaming mode or the desktop)
+  * The Summary lists every chosen item and where the PC starts
+  * The new user's Steam Machine setup runs during the install (`steamify-install`, a Calamares step
+    before cleanup): the first boot is already a Steam Machine
+  * Only what Steamify supports is offered: KDE Plasma, and the boot loaders Limine, systemd-boot and
+    GRUB (not rEFInd)
+* **Live session:** keeps CachyOS's own name; the power-off fix is built for the ISO's kernels, and
+  the login has the Vapor look
+
+**Fixes:**
+
+* **systemd-boot:** the installed system gets its "Linux Boot Manager" EFI boot entry, first in the
+  boot order. cachyos-installer runs `bootctl install` in a chroot, where bootctl leaves the EFI
+  variables alone, so the entry was missing: the PC could only boot through the disk's fallback path
+  (`\EFI\BOOT\BOOTX64.EFI`). Most PCs find it early and boot normally, but firmware that tries the
+  network first waits minutes on every boot (QEMU/OVMF: PXE, HTTP boot and the EFI shell come first),
+  and anything else that writes the fallback file (another OS) takes the boot over.
+  `steamify-install` now runs `bootctl --variables=yes install` from the live system;
+  the output is in `/var/log/steamify-bootentry.log`
+* **Installer:** Steamify's setup never asks for a password (its sudo rule is read after CachyOS's
+  `%wheel` rule); Calamares starts with the Boost version it was linked against
+* **Build:** finishes cleanly as root and reports no error after a successful build; the Steamify page's
+  Calamares module is built with the ISO and left out when Calamares' version differs
+
 # 26.08
 **Features:**