Issue #5: Enhanced Search Functionality

[D0T-B0X]

Description:
Current search only finds users by username. Need comprehensive search across users and posts with filters.

Current Limitations:

• Only searches usernames
• No post content search
• No filters or sorting
• No search history
• No autocomplete

Required Features:

1. Multi-Type Search

• Search users by username or name
• Search posts by content
• Toggle between "Users" and "Posts" tabs

2. Advanced Filters

• Date range (last 24h, 7d, 30d, all time)
• By user (when searching posts)
• Sort by: Relevance, Recent, Popular

3. UX Improvements

• Debounced search input (300ms delay)
• Loading skeleton while searching
• "No results" empty state
• Clear search button
• Recent search history (last 5)