feat: add keyboard navigation, escape-to-close modals, skip-to-content (A11Y-02)

All modals now close with Escape key. Interactive card divs respond to
Enter key. Skip-to-content link added to Dashboard layout. All Web5 and
Settings modals get role=dialog, aria-modal, and escape handlers.

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

neode-ui/src/views/Dashboard.vue

@@ -1,5 +1,7 @@
 <template>
   <div class="min-h-screen flex relative dashboard-view" :class="{ 'glass-throw-active': showZoomIn }">
+    <!-- Skip to main content link for keyboard users -->
+    <a href="#main-content" class="skip-to-content">Skip to main content</a>
     <!-- Background container with 3D perspective - full width to avoid letterboxing -->
     <div class="bg-perspective-container">
       <!-- Background - primary layer (visible for all routes, transitions out only for detail pages) -->
@@ -144,6 +146,7 @@
 
     <!-- Main Content (Xbox: Right goes here from sidebar) -->
     <main
+      id="main-content"
       data-controller-zone="main"
       class="flex-1 overflow-hidden relative pb-20 md:pb-0 glass-piece z-10"
       :class="{ 'glass-throw-main': showZoomIn }"