移动端下载器改版：重构为底部三标签的信息架构

- 以 TabBar + 三个视图（任务/搜索/设置）替换原有 DashBoard/Side/HentaiSearch 单页结构
- 拆分 TaskView / TaskRow / TaskDetailSheet / SearchView / SettingsView / AuthScreen
- 统一 theme.css 视觉规范，补 AppIcon 与缩略图工具 thumbnail.js 及其单测
- 提交弹层默认选中最高可用分辨率，缩略图加载失败走占位
- E站搜索结果与远端抽屉补回「在线看」入口

tests/thumbnail.test.mjs

@@ -0,0 +1,47 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import {ehThumbnailUrl, pickDefaultResolution} from '../src/utils/thumbnail.js'
+
+test('remote thumbnail paths are wrapped with the auth code', () => {
+    const url = ehThumbnailUrl('samples/thumb.png', 'abc123')
+    assert.match(url, /^https:\/\/downloader\.lionwebsite\.xyz\/GalleryManage\/ehThumbnail\?/)
+    assert.match(url, /path=samples%2Fthumb\.png/)
+    assert.match(url, /AuthCode=abc123/)
+})
+
+test('a missing thumbnail path produces no url', () => {
+    assert.equal(ehThumbnailUrl('', 'abc123'), '')
+    assert.equal(ehThumbnailUrl(undefined, 'abc123'), '')
+})
+
+test('the original resolution is preselected when offered', () => {
+    const chosen = pickDefaultResolution({
+        '800x': '37.53MiB',
+        '1280x': '66.57MiB',
+        '2560x': '84.01MiB',
+        'Original': '498.2MiB',
+    })
+    assert.equal(chosen, 'Original')
+})
+
+test('the original label is matched case-insensitively', () => {
+    assert.equal(pickDefaultResolution({'800x': '1MiB', 'original': '2MiB'}), 'original')
+})
+
+test('without an original the largest entry wins across units', () => {
+    const chosen = pickDefaultResolution({
+        '800x': '37.53MiB',
+        '2560x': '84.01MiB',
+        '2160x': '1.2GiB',
+    })
+    assert.equal(chosen, '2160x')
+})
+
+test('an empty or absent resolution map selects nothing', () => {
+    assert.equal(pickDefaultResolution({}), '')
+    assert.equal(pickDefaultResolution(undefined), '')
+})
+
+test('unparseable sizes fall back to the first entry instead of throwing', () => {
+    assert.equal(pickDefaultResolution({'800x': 'unknown', '1280x': 'unknown'}), '800x')
+})