feat(hud): Cyber HUD theme with GPU contact sonar (#706)

Add the opt-in Cyber HUD layout with coordinated map and cockpit panel
styling, GPU-only contact sonar (rings, range, power, opacity, sector) with
native-rendering fallback, and set_cyber_sonar voice controls. Sonar visual
style inspired by kk376's tactical naval sonar (#214).

Co-authored-by: Sameh Khamis <[email protected]>
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

src/ui/templates/context.html

@@ -62,6 +62,7 @@
           </div>
           <button class="panel-collapse-btn" data-collapse-target="global-context-panel" title="Expand panel">▶</button>
         </div>
+        <div class="cyber-panel-body" data-rail-scroller>
         <div class="global-context-modes" role="tablist" aria-label="Context mode">
           <button id="global-context-flights-btn" class="context-mode-button" type="button" role="tab" tabindex="0" aria-selected="false" aria-controls="context-flights-view" aria-label="CONTACTS" title="Cycles the nearest contacts of whatever type you select — planes, vessels, installations. Satellites track independently.">
             <span class="material-symbols-outlined" aria-hidden="true">radar</span>
@@ -237,6 +238,7 @@
             </div>
           </div>
         </section>
+        </div>
       </div>
     </div>
   </aside>