feat(bridge): desktop launcher entry + ParVagues wave icon

So 'parvagues' is findable in the KDE app menu (the Bridge runs headless as a
systemd service → had no .desktop, nothing to index). Entry opens the dashboard;
ParVagues two-tone wave SVG as the icon. Installed via symlink into
~/.local/share/applications + kbuildsycoca.

tools/bridge/parvagues-bridge.desktop

+[Desktop Entry]
+Type=Application
+Name=ParVagues GUI — The Bridge
+GenericName=ParVagues Dashboard
+Comment=Always-on ParVagues dashboard: perf toolbar + fleet hub (Foundry, Armada)
+Exec=xdg-open http://127.0.0.1:8773/
+Icon=/home/pln/Work/Sound/Tidal/tools/bridge/ui/parvagues.svg
+Terminal=false
+Categories=AudioVideo;
+Keywords=parvagues;tidal;livecoding;dashboard;perf;bridge;foundry;armada;wave;
+StartupNotify=false

tools/bridge/ui/parvagues.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="128" height="128" viewBox="0 0 128 128">
+  <rect width="128" height="128" rx="28" fill="#0a0a0a"/>
+  <g fill="none" stroke-linecap="round">
+    <path d="M10 78 Q 26 52 42 78 T 74 78 T 106 78 T 138 78"
+          stroke="#7c5cff" stroke-width="6" opacity="0.55"/>
+    <path d="M10 62 Q 26 34 42 62 T 74 62 T 106 62 T 138 62"
+          stroke="#d900ff" stroke-width="8"/>
+  </g>
+</svg>