quickshell: wallpaper switcher with per-wallpaper palettes

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CLAUDE.md

@@ -14,6 +14,7 @@ This is a NixOS flake-based configuration for multiple hosts:
 - `home-manager/` — Home Manager configuration (via NixOS module)
 - `services/` — modular service definitions, gated by hostname with `lib.mkIf`
 - `settings/` — shared settings (desktop, hyprland, quickshell, stylix, …)
+- `walls/` — wallpapers. Each gets a dark base16 palette generated at build time; the shell picks one at runtime (bar button → `settings/quickshell.nix`), so switching re-tints the shell without a rebuild. `walls/wallpaper.png` stays the build-time stylix scheme for everything else.
 - `modules/crowdsec/` — vendored crowdsec modules from nixpkgs PR #446307; delete once that PR lands in the pinned channel
 - `ports.toml` — WAN → LAN port forwards consumed by `services/router.nix`
 

settings/quickshell.nix

@@ -469,12 +469,26 @@ in
                     wallFile.writeAdapter();
                 }
 
-                property var pal: ({})
+                // The live palette. A JsonAdapter rather than a manual
+                // JSON.parse: its properties ARE QML properties, so a path
+                // change reloads the file and every colour binding below
+                // re-fires on its own. Defaults are stylix's build-time
+                // scheme (walls/wallpaper.png), which is also what shows if
+                // a palette file is ever missing or malformed.
                 property FileView palFile: FileView {
                     path: theme.currentWall ? theme.currentWall.palette : ""
                     printErrors: false
+                    // Synchronous: an async first read paints a frame in the
+                    // previous scheme on every switch.
                     blockLoading: true
-                    onLoaded: theme.pal = JSON.parse(text())
+                    adapter: JsonAdapter {
+                        id: pal
+                        property string base00: "${c.base00}"
+                        property string base03: "${c.base03}"
+                        property string base04: "${c.base04}"
+                        property string base05: "${c.base05}"
+                        property string base0D: "${c.base0D}"
+                    }
                 }
 
                 // ── Surfaces: one hue, three steps. base01/base02 are tints of
@@ -483,20 +497,16 @@ in
                 // purple card floating over a slate bar. Tinting keeps
                 // bar → card → hover reading as one stack. Two numbers, and
                 // they are the whole surface ladder.
-                //
+                readonly property color base00: "#" + pal.base00
-                // The "#${c.base00}" fallbacks are stylix's build-time scheme
-                // (walls/wallpaper.png): what shows for the frame or two
-                // before palFile lands, and if a palette file ever goes bad.
-                readonly property color base00: "#" + (pal.base00 || "${c.base00}")
                 readonly property color base01: Qt.lighter(base00, 1.7)  // card
                 readonly property color base02: Qt.lighter(base00, 2.4)  // hover / chip / track
                 // ── Ink, wallpaper-derived: base05 primary, base04 muted,
                 // base03 disabled (also the border colour).
-                readonly property color base03: "#" + (pal.base03 || "${c.base03}")
+                readonly property color base03: "#" + pal.base03
-                readonly property color base04: "#" + (pal.base04 || "${c.base04}")
+                readonly property color base04: "#" + pal.base04
-                readonly property color base05: "#" + (pal.base05 || "${c.base05}")
+                readonly property color base05: "#" + pal.base05
                 // The one themed accent: active, focused, selected, filled.
-                readonly property color base0D: "#" + (pal.base0D || "${c.base0D}")
+                readonly property color base0D: "#" + pal.base0D
 
                 // ── Status colours: fixed hues, pulled toward the theme.
                 // Sourcing these from stylix doesn't work — base08-base0F all