refactor(settings): thematic tab regroup + accordion sub-sections + in-page search (closes #257) (#259)

* refactor(settings): regroup tabs thematically + accordion sub-sections (progress on #257)

New tab structure: Servers (first) · Library · Audio · Lyrics · Appearance ·
Personalisation · Integrations · Input · Storage · System · Users.

Reusable SettingsSubSection (native <details>) wraps related settings per tab,
with an optional action slot for per-section reset buttons.

Moved:
- Lyrics sources + sidebar lyrics style → Lyrics
- Sidebar / artist layout / home customisers → Personalisation
- Last.fm / Discord / Bandsintown / Now-playing share → Integrations
  (with an opt-in privacy banner at the top)
- Tray / minimize / Linux smooth-scroll → System (new App-Verhalten group)
- Preload mini-player / custom titlebar / show artist images → Appearance visual options
- Language picker → System

Audio, Appearance and System tabs are now fully accordion-grouped.
Library tab reduced to Random Mix + Ratings accordions.
Servers tab is its own home (server cards + AudioMuse + logout) and the default
landing tab.

Indicators in the titlebar and offline banner route to the right tab.
EN + DE translations added for the new tab labels and privacy banner; other
locales fall back to English until the full i18n pass lands.

* refactor(settings): audio/input/storage/system accordions, in-page search, Navidrome focus

Settings refactor progress — every tab is now accordion-grouped:
- Audio: Output · Hi-Res · EQ · Playback · Next-track buffer
- Input: Keybindings · Global shortcuts (reset in accordion action slot)
- Storage: Offline · Downloads
- System: Language (default open) · Behavior · Backup · Logging · About · Contributors
- Contributors: own card grid with per-contributor expand, sorted by
  contribution count. Changelog accordion removed (release-notes link and
  "show changelog on update" toggle now live inside About).
- About: Navidrome focus; AI credit and Special Thanks removed; new
  Maintainers row (Psychotoxical + cucadmuh).

In-page search: magnifier icon next to the Settings title. Click opens a
240px search field. Filters the active tab's sub-sections by title match
(data-settings-search). Cross-tab search is tracked as a follow-up.

serverCompatible updated in all 8 locales from "Compatible with: Navidrome
Gonic Airsonic Subsonic" to a Navidrome-first wording that warns other
Subsonic-compatible servers may have reduced functionality.

Full i18n pass (tabLyrics/tabPersonalisation/tabIntegrations, aboutDesc,
privacy banner, etc. in fr/nl/zh/nb/ru/es) follows in a separate commit
after visual review.

* i18n(settings): complete localisation pass for refactored tabs

Added in all 8 locales (fr, nl, zh, nb, ru, es — en+de already in place):
- Tab labels: tabLibrary, tabServers, tabLyrics, tabPersonalisation, tabIntegrations
- inputKeybindingsTitle, searchPlaceholder, searchNoResults, aboutMaintainersLabel
- integrationsPrivacyTitle, integrationsPrivacyBody
- aboutContributorsCount_one/_other (ru also _few/_many for proper plural forms)
- aboutDesc rewritten to describe a Navidrome-focused player instead of a
  generic Subsonic-compatible one.

Removed dead keys in all 8 locales:
- aboutAiCredit, aboutSpecialThanksLabel — no longer rendered
- changelog — inline changelog accordion removed
- tabServer, tabGeneral — superseded by new tab structure

---------

Co-authored-by: Psychotoxical <dev@psysonic.app>

src/locales/zh.ts

@@ -461,7 +461,7 @@ export const zhTranslation = {
     serverFailed: '连接失败。',
     testBtn: '测试连接',
     testingBtn: '正在测试…',
-    serverCompatible: '兼容：Navidrome · Gonic · Airsonic · Subsonic',
+    serverCompatible: '专为 Navidrome 构建。其他兼容 Subsonic 的服务器（Gonic、Airsonic 等）可能功能受限，因为 Psysonic 使用了许多 Navidrome 特有的 API 端点。',
     userMgmtTitle: '用户管理',
     userMgmtDesc: '管理此服务器上的用户。需要管理员权限。',
     userMgmtNoAdmin: '需要管理员权限才能管理此服务器上的用户。',
@@ -636,18 +636,15 @@ export const zhTranslation = {
     clearFolder: '清除下载文件夹',
     logout: '退出登录',
     aboutTitle: '关于 Psysonic',
-    aboutDesc: '适用于 Subsonic 兼容服务器（Navidrome、Gonic 等）的现代桌面音乐播放器。基于 Tauri v2 和原生 Rust 音频引擎构建——轻量快速，功能丰富：波形进度条、同步歌词、Last.fm 集成、10 段均衡器、交叉淡入淡出、无缝播放、响度增益、流派浏览以及大量精美主题。',
+    aboutDesc: '一款专为 Navidrome 构建的现代桌面音乐播放器。使用 Subsonic API 以及 Navidrome 特有的扩展。基于 Tauri v2 和原生 Rust 音频引擎——轻量快速，功能丰富：波形进度条、同步歌词、Last.fm 集成、10 段均衡器、交叉淡入淡出、无缝播放、响度增益、流派浏览以及大量精美主题。',
     aboutLicense: '许可证',
     aboutLicenseText: 'GNU GPL v3 — 在相同许可证下可自由使用、修改和分发。',
     aboutRepo: 'GitHub 上的源代码',
     aboutVersion: '版本',
     aboutBuiltWith: '使用 Tauri · React · TypeScript · Rust/rodio 构建',
-    aboutAiCredit: '在 Anthropic 的 Claude Code 支持下开发',
     aboutReleaseNotesLabel: '版本说明',
     aboutReleaseNotesLink: '打开此版本的新功能',
     aboutContributorsLabel: '贡献者',
-    aboutSpecialThanksLabel: '特别感谢',
-    changelog: '更新日志',
     showChangelogOnUpdate: '更新时显示"新功能"',
     showChangelogOnUpdateDesc: '更新后在「正在播放」上方显示一个低调的更新日志横幅。点击打开发行说明，X 按钮关闭。',
     randomMixTitle: '随机混音',
@@ -660,6 +657,19 @@ export const zhTranslation = {
     tabAudio: '音频',
     tabStorage: '存储与下载',
     tabAppearance: '外观',
+    tabLibrary: '媒体库',
+    tabServers: '服务器',
+    tabLyrics: '歌词',
+    tabPersonalisation: '个性化',
+    tabIntegrations: '集成',
+    inputKeybindingsTitle: '键盘快捷键',
+    aboutContributorsCount_one: '{{count}} 项贡献',
+    aboutContributorsCount_other: '{{count}} 项贡献',
+    searchPlaceholder: '搜索设置…',
+    searchNoResults: '此标签页中没有匹配的设置。请尝试其他标签页。',
+    aboutMaintainersLabel: '维护者',
+    integrationsPrivacyTitle: '隐私说明',
+    integrationsPrivacyBody: '此标签页中的所有集成均为 <strong>选择加入</strong>，启用后会向外部服务或您的 Navidrome 服务器发送数据。Last.fm 接收您的收听历史，Discord 在您的个人资料中显示正在播放的曲目，Bandsintown 会按艺人查询以获取巡演日期，"正在播放" 分享会向您 Navidrome 服务器的其他用户公开您当前的曲目。如果您不需要这些功能，只需将相应部分保持停用即可。',
     homeCustomizerTitle: '首页',
     sidebarTitle: '侧边栏',
     sidebarReset: '重置为默认',
@@ -676,7 +686,6 @@ export const zhTranslation = {
     randomNavSplitTitle: '拆分混音导航',
     randomNavSplitDesc: '在侧边栏中将"随机混音"和"随机专辑"显示为独立条目，而非"创建混音"合并入口。',
     tabInput: '输入',
-    tabServer: '服务器',
     tabUsers: '用户',
     tabSystem: '系统',
     loggingTitle: '日志记录',
@@ -687,7 +696,6 @@ export const zhTranslation = {
     loggingExport: '导出日志',
     loggingExportSuccess: '日志已导出（{{count}} 行）。',
     loggingExportError: '无法导出日志。',
-    tabGeneral: '通用',
     ratingsSectionTitle: '评分',
     ratingsSkipStarTitle: '跳过以评 1 星',
     ratingsSkipStarDesc: