overhaul settings: split into routed sub-tabs, add server logs, changelog, reusable setting components

- Rename Server tab to Settings with horizontal sub-tab navigation (General, Generation, GPU, Logs, Changelog)
- All sub-tabs are proper routes under /settings/* with /server redirect for backwards compat
- General: connection settings, link cards (docs + discord), API reference card, app updates
- Generation: auto-chunking, crossfade, normalize, autoplay as SettingRow components
- GPU: info card with platform-aware icons (Apple logo for MPS), CUDA management, explainer text
- Logs: real-time server log viewer piped from Tauri sidecar via event system (Tauri-only)
- Changelog: parsed from CHANGELOG.md at build time via Vite virtual module plugin
- New reusable SettingRow/SettingSection components for consistent settings layout
- New Toggle (switch) UI component replacing checkboxes in settings
- Toast viewport now offsets when audio player is open
- Sidebar stays active on settings sub-routes (fuzzy matching)

app/src/lib/utils/parseChangelog.ts

@@ -0,0 +1,37 @@
+export interface ChangelogEntry {
+  version: string;
+  date: string | null;
+  body: string;
+}
+
+/**
+ * Parses a Keep-a-Changelog style markdown string into structured entries.
+ *
+ * Splits on `## [version]` headings and extracts the version + date from each.
+ * The body is the raw markdown between headings (trimmed), with the leading
+ * `# Changelog` title and trailing link references stripped.
+ */
+export function parseChangelog(raw: string): ChangelogEntry[] {
+  const entries: ChangelogEntry[] = [];
+
+  // Strip trailing link reference definitions (e.g. [0.1.0]: https://...)
+  const cleaned = raw.replace(/^\[[\w.]+\]:.*$/gm, '').trimEnd();
+
+  // Match `## [version]` or `## [version] - date`
+  const headingRe = /^## \[(.+?)\](?:\s*-\s*(.+))?$/gm;
+  const matches = [...cleaned.matchAll(headingRe)];
+
+  for (let i = 0; i < matches.length; i++) {
+    const match = matches[i];
+    const version = match[1];
+    const date = match[2]?.trim() || null;
+
+    const start = match.index! + match[0].length;
+    const end = i + 1 < matches.length ? matches[i + 1].index! : cleaned.length;
+    const body = cleaned.slice(start, end).trim();
+
+    entries.push({ version, date, body });
+  }
+
+  return entries;
+}