fix: design ux improvements

[isekovanic]

🎯 Goal

Fix a set of design regressions across poll headers, audio attachments, message metadata, composer/header borders, bottom navigation and stacked avatars so they match the current design token guidance and visual specs.

🛠 Implementation details

• Updated Poll Results and Poll Creation headers to use a secondary ghost icon only back button with the new ArrowLeft icon
• Added ArrowLeft, derived from the existing ArrowUp path with SVG rotation, including RTL aware direction
• Fixed single audio attachments in quoted replies without captions so they render directly on the message bubble surface instead of adding the darker audio fill
• Preserved the filled audio background when the reply has a caption or multiple attachments
• Updated composer/header separator borders to use semantics.borderCoreSubtle
• Updated sent message footer spacing so the read receipt and timestamp use spacingXxs
• Updated SampleApp bottom tabs to use semantics.backgroundCoreElevation1 and semantics.borderCoreSubtle
• Added visible semantic borders to UserAvatarStack avatars using semantics.borderCoreInverse
• Added theme.avatarStack.userAvatarWrapper so the new avatar stack style remains theme compliant

🎨 UI Changes

iOS

Before	After

Android

Before	After

🧪 Testing

☑️ Checklist

• I have signed the Stream CLA (required)
• PR targets the develop branch
• Documentation is updated
• New code is tested in main example apps, including all possible scenarios
  • SampleApp iOS and Android
  • Expo iOS and Android

[Stream-SDK-Bot]

SDK Size

title	develop	branch	diff	status
js_bundle_size	367 KB	368 KB	+1824 B	🔴