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/features/room/RoomInput.tsx

@@ -879,7 +879,7 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
                     ...
                   </Text>
                 ) : (
-                  <Icon src={Icons.Pin} size="100" />
+                  <Icon src={Icons.SpaceGlobe} size="100" />
                 )}
               </IconButton>
               <VoiceMessageRecorder onSend={handleVoiceSend} />