Consolidate omarchy-shell colors into a single shell.toml surface

Five plugins each owned their own colors.toml watcher with subtly
different parsers, plus two ad-hoc per-theme override files
(notifications.json, image-picker-colors.json). This collapses all of
that into one source of truth: Commons/Color.qml watches colors.toml +
shell.toml and exposes Color.bar.*, Color.popups.*, Color.notifications.*,
Color.menu.*, Color.imagePicker.* for every surface to bind to.

shell.toml is generated by the existing template pipeline from
default/themed/shell.toml.tpl. Themes can ship their own shell.toml to
override individual keys; everything missing falls back to the
foundational palette via root.pick(). Settings panel is intentionally
not themable beyond the foundational tokens.

last-horizon and solitude ship a minimal shell.toml to preserve their
historical 'notification border matches Hyprland active border'
behavior, which previously came from parsing the theme's hyprland.conf
(now removed).

default/quickshell/omarchy-shell/plugins/menu/Menu.qml

@@ -2,6 +2,7 @@ import Quickshell
 import Quickshell.Io
 import Quickshell.Wayland
 import QtQuick
+import qs.Commons
 
 Item {
   id: root
@@ -15,22 +16,13 @@ Item {
   // Plugin lifecycle hooks. The host calls open(payloadJson) after
   // `omarchy-shell-ipc shell summon omarchy.menu ...` and close() when hidden.
   property string pendingInitialMenu: "root"
-  property string pendingColorsRaw: ""
-
-  function decodeBase64(value) {
-    var s = String(value || "")
-    if (!s) return ""
-    try { return Qt.atob(s) } catch (e) { return s }
-  }
 
   function open(payloadJson) {
     var payload = ({})
     try { payload = JSON.parse(payloadJson || "{}") } catch (e) { payload = ({}) }
 
     root.pendingInitialMenu = payload.initialMenu || payload.menu || "root"
-    root.pendingColorsRaw = payload.colorsRawBase64 ? root.decodeBase64(payload.colorsRawBase64) : (payload.colorsRaw || "")
     if (payload.fontFamily) root.fontFamily = payload.fontFamily
-    if (root.pendingColorsRaw) root.loadColors(root.pendingColorsRaw)
 
     root.openExistingMenu(root.pendingInitialMenu)
   }
@@ -40,7 +32,6 @@ Item {
   }
 
   property string fontFamily: Quickshell.env("OMARCHY_MENU_FONT") || "monospace"
-  property string colorsFile: Quickshell.env("OMARCHY_MENU_COLORS_FILE") || (Quickshell.env("HOME") + "/.config/omarchy/current/theme/colors.toml")
   property string styleFile: Quickshell.env("OMARCHY_MENU_STYLE_FILE") || (Quickshell.env("HOME") + "/.local/state/omarchy/toggles/quickshell-menu.json")
   // JSONC menu definitions. The shell parses both at startup and merges
   // the user file on top of the defaults, so the keybind → IPC → visible
@@ -61,9 +52,10 @@ Item {
   property var navStack: []
   property var providersLoaded: ({})
   property var providerQueue: []
-  property color accent: "#89b4fa"
-  property color background: "#101315"
-  property color foreground: "#cacccc"
+  // Bound to the central [menu] section in shell.toml via Color.qml.
+  property color accent: Color.menu.selected
+  property color background: Color.menu.background
+  property color foreground: Color.menu.text
   property color border: foreground
   property int cornerRadius: 0
   property int contentMargin: 18
@@ -624,18 +616,6 @@ Item {
     Qt.callLater(function() { keyCatcher.forceActiveFocus() })
   }
 
-  function loadColors(raw) {
-    var lines = String(raw || "").split("\n")
-    for (var i = 0; i < lines.length; i++) {
-      var match = lines[i].match(/^\s*([A-Za-z0-9_-]+)\s*=\s*["']?(#[0-9A-Fa-f]{6})/)
-      if (!match) continue
-      if (match[1] === "foreground") foreground = match[2]
-      else if (match[1] === "background") background = match[2]
-      else if (match[1] === "color4" || match[1] === "accent") accent = match[2]
-    }
-    border = foreground
-  }
-
   function loadStyle(raw) {
     try {
       var style = JSON.parse(raw || "{}")
@@ -811,13 +791,6 @@ Item {
     }
   }
 
-  FileView {
-    path: root.colorsFile
-    watchChanges: true
-    onLoaded: root.loadColors(text())
-    onFileChanged: { reload(); root.loadColors(text()) }
-  }
-
   FileView {
     path: root.styleFile
     watchChanges: true