slskd: /soulseek search + downloads on the Workspace/Panel framework

Two panels (search + transfers) via WorkspaceView, coordinating over the
soulseek:refresh channel. Adds the page-title rule and documents the
route conventions in CLAUDE.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/apps/officer-web/state/usePageTitle.ts

@@ -16,6 +16,7 @@ const RULES: TitleRule[] = [
   { match: (p) => p.startsWith('/email'), title: 'Email' },
   { match: (p) => p.startsWith('/files'), title: 'Files' },
   { match: (p) => p.startsWith('/music'), title: 'Music' },
+  { match: (p) => p.startsWith('/soulseek'), title: 'Soulseek' },
   { match: (p) => p.startsWith('/system-monitor'), title: 'System Monitor' },
   { match: (p) => p.startsWith('/code-editor'), title: 'Code Editor' },
   { match: (p) => p.startsWith('/projects'), title: 'Projects' },