feat(appearance): wallpaper picker and scheme switcher

One drawer for how the desktop looks, on SUPER+Return, replacing the
qarma file dialog that key used to open. wallp is untouched and still
does the work: the panel calls it with H= and V= and it still runs from
a terminal.

Clicking a thumbnail stages it rather than setting it, so both screens
can be composed before anything changes and Apply is a single wallp
call. The mock screens show the result: the staged pick where there is
one, what is set where there is not, and the hovered thumbnail on the
targeted screen. They are drawn at the real proportions from hyprctl
monitors, DP-3 upright because it has transform=1, centred against each
other as Hyprland has them.

The scheme tab reads the palette pair unified-desktop-theme keeps for
each scheme, so the swatches are that scheme's real colours and the list
needs no edit when a scheme is added. Applying writes roles.conf and
runs install.sh, and reloads nothing, because install.sh reloads
nothing: the panel says what is still showing the old scheme rather than
pretending the switch is done.

Two QML traps are documented in AGENTS.md because neither announces
itself: there is no String.matchAll, which threw inside a try and left
every swatch empty, and assigning running = true to an already-running
Process does nothing, which stopped the scheme loader after the first
file.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G7NRsGyF9jGfPYS4zPqpN7

1 files changed, 6 insertions, 0 deletions

diff --git a/AGENTS.md b/AGENTS.md
index e7e7f65..c3cf2ef 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -10,6 +10,7 @@ them runs alone, and running one does not require the others.
 
     volume-osd/     volume for output and input, plus what is playing
     vm-manager/     libvirt drawer: state, live stats, snapshots
+    appearance/     wallpaper picker and colour scheme switcher
 
 Both are started from `~/.config/hypr/sections/autostart.lua` and keep running
 for the whole session.
@@ -62,6 +63,11 @@ changing that component. The ones that generalise:
   `Keys.onEscapePressed` on a `PanelWindow` never fires.
 - **A `Row` sizes to its children, not its parent.** Fixed child widths inside
   one overflowed the panel and pushed a button past its edge.
+- **QML's JS engine has no `String.matchAll`.** It throws, and inside a `try`
+  that looks like a parser quietly returning nothing. Use an `exec` loop.
+- **Assigning `running = true` to a `Process` that is already running does
+  nothing.** Reusing one `Process` for a sequence of commands needs
+  `running = false` immediately before each start.
 - **libvirt's own memory and disk figures are not what they look like.**
   `balloon.current` is memory allocated to the VM and reads full forever;
   `block.allocation` is qcow2 growth on the host, not usage inside the guest.