fix: Add optimistic cache updates for tweet deletion and user actions - #189

Summary

This PR includes multiple fixes for cache invalidation and UI improvements.

Changes

🔄 Delete Mutation Cache Updates (useTweetActions.ts)

• Added optimistic cache updates for searchPosts, explore, categoryPosts, and tweet-quotes when deleting tweets
• Added cache invalidation in onSuccess and onError handlers
• Created new remove functions in cacheUtils.ts:
  • removeTweetFromSearchPostsCache
  • removeTweetFromExploreCache
  • removeTweetFromCategoryPostsCache
  • removeTweetFromQuotesCache

👥 Search Users Cache on Follow/Block (useFollowUser.ts, useBlockUser.ts)

• Added ISearchUsersMappedPageData type to search types
• Follow/unfollow now updates search users cache immediately
• Block/unblock now removes users from search results cache
• Added cache invalidation on error

📹 Video Duration Placeholder (useMediaViewerControls.ts, MediaViewerModal.tsx)

• Shows --:-- for invalid time values (NaN, Infinity, negative)
• Shows --:-- for duration until video metadata loads (duration > 0)

🔧 MediaViewerModal iOS Fix (MediaViewerModal.tsx)

• Moved CreatePostModal inside the main Modal component
• Fixes reply/quote modal not opening on iPhone

Testing

• Tested delete mutation updates search/explore/quotes lists
• Tested follow/unfollow updates search users list
• Tested block removes user from search results
• Tested video duration shows placeholder until loaded