fix: clean up ComponentOverrides types to not leak displayName

[oliverlaz]

🎯 Goal

Components with .displayName assignments (e.g. ChannelPreviewView.displayName = '...') caused typeof to include displayName: string (required) in the inferred DEFAULT_COMPONENTS type. This leaked into ComponentOverrides, forcing integrators to set displayName on their custom component overrides.

🛠 Implementation details

• NormalizeComponents mapped type — normalizes each entry in DEFAULT_COMPONENTS to React.ComponentType<P>, where displayName is optional (displayName?: string). Applied via a typed cast on the export so the raw object keeps its runtime shape.
• OptionalComponentOverrides interface — optional component slots (no default implementation) are moved out of the runtime object into a standalone interface. This eliminates undefined as React.ComponentType<any> | undefined casts and eslint-disable comments.
• Proper props types — MessageLocation, MessageText, and Input now have real prop types instead of React.ComponentType<any>. Components rendered with no props use React.ComponentType (defaults to {}).
• Removed stale PLAN.md from the componentsContext directory.

🎨 UI Changes

No UI changes — types only.

🧪 Testing

• npx tsc --noEmit passes with zero errors
• Verified via TS compiler API that ChannelPreview on DEFAULT_COMPONENTS resolves to ComponentType<...> with ?displayName: string | undefined (optional)

☑️ 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	354 KB	354 KB	0 B	🟢