feat(grub): rebuild on every wallpaper change via udt-grub

GRUB's background is a wallpaper snapshot, but only install.sh rebuilt it,
so a wallpaper change left the /boot copy stale with no hint. udt-grub now
holds the build-and-print logic; install.sh runs it in the foreground and
udt-accent starts it detached next to udt-homepage. A stale installed theme
gets a notification carrying the root copy command. A flock serialises the
two runs install.sh triggers, since build swaps dist/udt in by rename.

AGENTS.md: udt-accent writes seven outputs (SDDM was missing), and names
the two detached helpers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 12 insertions, 6 deletions

diff --git a/AGENTS.md b/AGENTS.md
index e6b0960..6218fb6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -24,9 +24,11 @@ Sibling checkouts are wired from here, each skipped when not cloned:
 `~/.config/conky/`) and `hypr-theme`, which is the whole of `~/.config/hypr` as
 one symlink. A real `~/.config/hypr` directory is left alone with a warning.
 `grub-theme-udt` is SDDM's shape: udt-palette renders its `theme.txt.in`,
-`install.sh` runs its `build` as the user, then prints the root copy. A copy,
-not a link, because GRUB reads `/boot` before `/home` is mounted; it needs
-rerunning after a scheme or wallpaper change.
+`bin/udt-grub` runs its `build` as the user, then prints the root copy. A copy,
+not a link, because GRUB reads `/boot` before `/home` is mounted, so it goes
+stale on a scheme or wallpaper change. `install.sh` runs `udt-grub` in the
+foreground and `udt-accent` starts it detached, and when an installed theme
+differs from the new build the root command arrives as a notification.
 Its panel title is `PRETTY_HOSTNAME` from `/etc/machine-info`, which
 `bin/udt-machine-name` writes (root, run by the user; there is no
 hostnamectl without systemd). It rewrites that one key and keeps the rest.
@@ -166,12 +168,16 @@ One colour moves: `@accent`. `bin/udt-accent` reads the current wallpaper,
 extracts its signature colour, and snaps it to the nearest of ten Catppuccin
 accents by perceptual hue in CIELAB. `wallp` calls it on every wallpaper change.
 
-It writes six things: `~/.cache/udt/udt-accent.rasi` (rofi),
+It writes seven things: `~/.cache/udt/udt-accent.rasi` (rofi),
 `~/.cache/udt/udt-border.lua` (Hyprland), `~/.cache/udt/hyprlock-border.conf`
 (hyprlock, the same three hues as the window border, as a hyprlang gradient),
 `~/.cache/wal/colors.json` (Firefox, via pywalfox),
-`~/.cache/udt/udt-palette.qml` (quickshell), and the accent substitution in
-Sublime's installed `Packages/User/udt.sublime-color-scheme`.
+`~/.cache/udt/udt-palette.qml` (quickshell),
+`~/.local/share/udt/sddm-theme.conf` (the SDDM greeter, palette plus wallpaper,
+read through a root-made `theme.conf.user` symlink), and the accent
+substitution in Sublime's installed `Packages/User/udt.sublime-color-scheme`.
+It then starts `udt-homepage` and `udt-grub` detached, for the two outputs
+that need a root step on another filesystem or host.
 
 **Sublime's accent is replaced, not substituted into a placeholder.** Its
 colour scheme cannot cascade, so the accent has to live in the one generated