feat: replace modal editors with floating popover panel for sites, links, and simulations (#804)

Introduces MapEditorPanel — a floating popover anchored to its trigger button — that
unifies edit and create flows for site library entries, links, and simulation presets.
Dismissed by ESC, outside-click, or ×; renders as a bottom sheet on mobile.
Old ModalOverlay blocks for resourceDetailsPopup and linkModal are now dead code.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: wilhel1812

src/components/AppShell.tsx

@@ -37,6 +37,7 @@ import SimulationLibraryPanel from "./SimulationLibraryPanel";
 import WelcomeModal from "./WelcomeModal";
 import { Sidebar } from "./Sidebar";
 import { SettingsPanel } from "./settings/SettingsPanel";
+import { MapEditorPanel } from "./map/MapEditorPanel";
 import { MobileWorkspaceTabs } from "./app-shell/MobileWorkspaceTabs";
 import { useOnboardingFlow } from "./app-shell/useOnboardingFlow";
 
@@ -2458,6 +2459,7 @@ export function AppShell() {
           </div>
         </ModalOverlay>
       ) : null}
+      <MapEditorPanel isMobile={isMobileViewport} />
     </main>
   );
 }