fix(a11y): reduced-motion for spinner/call-avatar; tap-to-skip boot; AA accent contrast

- SendingSpinClass and CallAvatarAnimation respect prefers-reduced-motion
  (static opacity fallback), matching MsgAppearClass.
- Terminal boot overlay dismisses on click/tap and is aria-hidden.
- Primary.Main: Midnight #6b7ca8 -> #6f80aa (4.29 -> 4.51:1), Lotus
  Terminal Light #c44e00 -> #ba4a00 (4.14 -> 4.52:1), hue preserved.

Fixes #84
Fixes #86
Fixes #52

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/lotus-boot.ts

@@ -34,6 +34,8 @@ export function runLotusBootSequence(force = false): void {
 
   const overlay = document.createElement('div');
   overlay.id = 'lt-boot';
+  // Decorative boot animation, not content — hide it from assistive tech.
+  overlay.setAttribute('aria-hidden', 'true');
   overlay.style.cssText = [
     'position:fixed',
     'inset:0',
@@ -79,6 +81,7 @@ export function runLotusBootSequence(force = false): void {
   const dismiss = (): void => {
     clearInterval(interval);
     document.removeEventListener('keydown', onKey);
+    overlay.removeEventListener('click', dismiss);
     overlay.style.transition = 'opacity 0.4s ease';
     overlay.style.opacity = '0';
     setTimeout(() => overlay.remove(), 400);
@@ -88,6 +91,9 @@ export function runLotusBootSequence(force = false): void {
     if (e.key === 'Escape') dismiss();
   };
   document.addEventListener('keydown', onKey);
+  // No touch/click dismiss previously existed — mouse/touch users had no way
+  // to skip besides the keyboard-only Escape hint.
+  overlay.addEventListener('click', dismiss);
 
   let i = 0;
   let text = '';