Cleaner Slash Command Permission UI

The permission confirmation prompt for slash commands now displays more user-friendly information:

• Title changed from generic "Tool use" to specific "Slash command"
• Shows the actual command string instead of SlashCommand(command-name)
• Displays command description instead of technical Execute slash command: /command
• Includes command metadata for better context-aware routing
• Evidence: UI component changes at lines 72425-72430 in permission confirmation renderer, metadata addition at line 65680