feat(themes): Solarized and One theme plugins (#92)

Solarized Light/Dark and One Light/Dark ship as theme plugins (plugins/theme-solarized, plugins/theme-one) with complete UI tokens, editor schemes and terminal colours, and the original palettes' MIT notices. Installing a plugin now also copies its LICENSE/NOTICE/COPYING.

Theme handling that benefits every plugin theme:
- The last plugin theme is restored before first paint (splash, workbench); the native window background follows the theme.
- HSL / color-mix() / var() colours are resolved to RGB for native windows, the Settings window and Mermaid.
- Mermaid, the terminal and editor schemes follow switches between two themes of the same kind.
- An explicitly chosen editor scheme wins over a plugin theme's editor colours.

Supersedes #85.

Co-authored-by: bghtyu <[email protected]>
Claude-Session: https://claude.ai/code/session_01VUYsdXA2nkF5v6zsC93dpn

src/features/settings/__tests__/dialog.test.tsx

@@ -1,6 +1,6 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { act, fireEvent, render, screen, within } from "@testing-library/react";
-import type { Settings } from "@/platform/ipc";
+import { commands, type Settings } from "@/platform/ipc";
 
 const settingsSet = vi.fn();
 const settingsGet = vi.fn();
@@ -282,3 +282,29 @@ describe("Settings dialog", () => {
     expect(within(dialog).getByLabelText("UI font size")).toHaveValue("13");
   });
 });
+
+describe("native Settings window background", () => {
+  it.each([
+    ["a hex frame", "#26282c", "", "#26282c"],
+    ["an hsl() frame", "hsl(220, 13%, 15%)", "rgb(33, 37, 43)", "#21252b"],
+    [
+      "a translucent color-mix() frame",
+      "color-mix(in srgb, #8040bf 80%, transparent)",
+      "color(srgb 0.5 0.25 0.75 / 0.8)",
+      "#8040bfcc",
+    ],
+  ])("sends %s as hex, the colour format the window command parses", async (_name, token, resolved, hex) => {
+    const native = vi.spyOn(commands, "windowOpenSettings").mockResolvedValue({ status: "ok", data: null });
+    const computed = vi
+      .spyOn(globalThis, "getComputedStyle")
+      .mockReturnValue({ getPropertyValue: () => token, color: resolved } as unknown as CSSStyleDeclaration);
+    try {
+      await executeAction("file.settings", "appearance");
+      expect(native).toHaveBeenCalledWith("appearance", false, hex);
+      expect(useSettingsDialog.getState().open).toBe(false);
+    } finally {
+      computed.mockRestore();
+      native.mockRestore();
+    }
+  });
+});

src/features/settings/index.ts

@@ -17,6 +17,7 @@ import { call, commands, isTauri } from "@/platform/ipc";
 import { isPopupOpen, lazyComponent } from "@/ui";
 import { loadSettings, useProject } from "@/platform/project";
 import { provideSettingsSearchIndex, registerOverlay } from "@/workbench/contributions";
+import { windowBackgroundHex } from "@/workbench/theme";
 import { LazySettingsDialog, loadBuiltinPages, unloadBuiltinPages } from "./dialog/LazySettingsDialog";
 import {
   closeSettings,
@@ -85,8 +86,7 @@ function settingsActions(open: (page?: string, newProjects?: boolean) => void):
 async function showSettings(page?: string, newProjects = false) {
   if (isTauri()) {
     try {
-      const frame = getComputedStyle(document.documentElement).getPropertyValue("--bg-frame").trim();
-      await call(commands.windowOpenSettings(page ?? null, newProjects, frame || null));
+      await call(commands.windowOpenSettings(page ?? null, newProjects, windowBackgroundHex()));
       return;
     } catch (e) {
       console.warn("settings window unavailable, using the dialog", e);