Fix shell details: distro name, storage path only in footer

- OS name comes from /etc/os-release (e.g. 'CachyOS Linux'), mirroring
  the original app's os_utils; macOS/Windows get proper names too
- Status pill shows the name as-is instead of uppercasing it
- Removed the watched-folder path next to the logo; it now appears only
  in the footer strip (spec updated to match)

frontend/src/components/StatusPill.tsx

@@ -34,7 +34,7 @@ export function StatusPill({ status }: { status?: SystemStatus }) {
       <span>{status.git_hash}</span>
       <span className="text-ctp-surface2">·</span>
       <OsIcon className="h-3 w-3" />
-      <span>{status.os.name.toUpperCase()}</span>
+      <span>{status.os.name}</span>
       <span className="text-ctp-surface2">·</span>
       <span>{formatMs(status.server_time_ms)}</span>
       {status.e621_time_ms !== null ? (