feat: persist complete multitheme palettes

src/lib/theme-settings.test.ts

@@ -0,0 +1,22 @@
+import { describe, expect, it } from "vitest";
+import { presetSettings, settingKey } from "@/lib/theme-settings";
+import { PRESETS, THEME_COLOR_KEYS } from "@/lib/theme-presets";
+
+describe("theme settings mapping", () => {
+  it("keeps legacy light keys and suffixes dark keys", () => {
+    expect(settingKey("color_primary", "light")).toBe("color_primary");
+    expect(settingKey("color_primary", "dark")).toBe("color_primary_dark");
+  });
+
+  it("serializes every preset key for both modes without duplicates", () => {
+    const settings = presetSettings(PRESETS.Ocean);
+    const keys = settings.map(([key]) => key);
+
+    expect(settings).toHaveLength(THEME_COLOR_KEYS.length * 2);
+    expect(new Set(keys).size).toBe(keys.length);
+    for (const key of THEME_COLOR_KEYS) {
+      expect(keys).toContain(key);
+      expect(keys).toContain(`${key}_dark`);
+    }
+  });
+});

src/lib/theme-settings.ts

@@ -0,0 +1,11 @@
+import { THEME_COLOR_KEYS, type ThemeColorKey, type ThemeMode, type ThemePreset } from "@/lib/theme-presets";
+
+export function settingKey(key: ThemeColorKey, mode: ThemeMode): string {
+  return mode === "light" ? key : `${key}_dark`;
+}
+
+export function presetSettings(preset: ThemePreset): Array<[string, string]> {
+  return (["light", "dark"] as const).flatMap((mode) =>
+    THEME_COLOR_KEYS.map((key) => [settingKey(key, mode), preset[mode][key]] as [string, string]),
+  );
+}