feat: configure launcher color scheme

Sources/Conjure/LauncherBackground.swift

@@ -1,34 +1,44 @@
 import AppKit
 
 @MainActor
-enum SunsetPalette {
-    static let background = NSColor(srgbRed: 0.12, green: 0.09, blue: 0.08, alpha: 0.55)
-    static let text = NSColor(srgbRed: 1.00, green: 0.89, blue: 0.71, alpha: 1)
-    static let secondaryText = NSColor(srgbRed: 0.85, green: 0.78, blue: 0.65, alpha: 1)
-    static let accent = NSColor(srgbRed: 0.95, green: 0.58, blue: 0.23, alpha: 1)
+enum ThemePalette {
+    private static let loaded: (scheme: ColorScheme, error: String?) = {
+        do {
+            return (try ColorScheme.load(from: ColorScheme.configurationDirectory), nil)
+        } catch {
+            return (.sunset, "Color configuration: \(error.localizedDescription)\nUsing the built-in sunset palette. Fix the file and restart Conjure.")
+        }
+    }()
+    static let configurationError = loaded.error
+    static let background = loaded.scheme.background.withAlphaComponent(0.55)
+    static let text = loaded.scheme.text
+    static let secondaryText = loaded.scheme.secondaryText
+    static let accent = loaded.scheme.accent
     static let selectionFill = accent.withAlphaComponent(0.12)
     static let selectionBorder = accent.withAlphaComponent(0.30)
-    static let ember = NSColor(srgbRed: 0.76, green: 0.27, blue: 0.18, alpha: 1)
+    static let glow = loaded.scheme.glow
+    static let keyBackground = loaded.scheme.keyBackground.withAlphaComponent(0.5)
+    static let error = loaded.scheme.error
 }
 
 @MainActor
 final class LauncherBackground: NSView {
     weak var canvas: NSView?
     private let amber = NSGradient(colors: [
-        SunsetPalette.accent.withAlphaComponent(0.18),
-        SunsetPalette.accent.withAlphaComponent(0.065),
-        SunsetPalette.accent.withAlphaComponent(0),
+        ThemePalette.accent.withAlphaComponent(0.18),
+        ThemePalette.accent.withAlphaComponent(0.065),
+        ThemePalette.accent.withAlphaComponent(0),
     ])!
     private let ember = NSGradient(colors: [
-        SunsetPalette.ember.withAlphaComponent(0.26),
-        SunsetPalette.ember.withAlphaComponent(0.10),
-        SunsetPalette.ember.withAlphaComponent(0),
+        ThemePalette.glow.withAlphaComponent(0.26),
+        ThemePalette.glow.withAlphaComponent(0.10),
+        ThemePalette.glow.withAlphaComponent(0),
     ])!
 
     override func hitTest(_ point: NSPoint) -> NSView? { nil }
 
     override func draw(_ dirtyRect: NSRect) {
-        SunsetPalette.background.setFill()
+        ThemePalette.background.setFill()
         dirtyRect.fill()
         let canvasBounds = canvas.map { convert($0.bounds, from: $0) } ?? bounds
         let upperGlow = NSPoint(x: canvasBounds.minX + canvasBounds.width * 0.58,