ui: visual polish — animations, icons, and interaction improvements

- Spin animation on ⟳ delivery status during SENDING/ENCRYPTING states
- Pulsing ● dot on PTT LIVE badge (pttLivePulse keyframe)
- Read receipt pill: hover scale/opacity transition, symmetric padding
- PiP resize handles: larger dots (5px), wider hit area (24px), higher contrast
- ForwardMessageDialog: position:relative on scroll container, spinner overlay 0.35 opacity
- Boot sequence: 45ms interval (was 65ms), brighter ESC hint (0.55 opacity)
- Location button: Icons.Pin → Icons.SpaceGlobe (globe icon)

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

src/app/styles/Animations.css.ts

@@ -1,6 +1,11 @@
 import { keyframes, style } from '@vanilla-extract/css';
 import { color, toRem } from 'folds';
 
+const spin = keyframes({
+  from: { transform: 'rotate(0deg)' },
+  to: { transform: 'rotate(360deg)' },
+});
+
 const wobble = keyframes({
   '0%': {
     transform: 'translateX(0) rotateZ(0deg)',
@@ -45,3 +50,9 @@ export const CallAvatarAnimation = style({
   animation: `${wobble} 2000ms ease-in-out, ${glowPulse} 2000ms ease-out`,
   animationIterationCount: 'infinite',
 });
+
+export const SendingSpinClass = style({
+  display: 'inline-block',
+  animation: `${spin} 900ms linear infinite`,
+  transformOrigin: 'center',
+});