- Add CODEBASE_GUIDE.md with comprehensive documentation:
  * Architecture overview with visual diagrams
  * Detailed explanation of the 'AI-guided frontier map' system
    (clarifying it's procedural generation, not actual AI/ML)
  * Pygame UI issues and refactoring recommendations
  * Extension guide for adding new classes, features, and items

- Add ui/pygame_ui_refactored.py as alternative implementation:
  * Separates concerns into Panel, LayoutManager, GameRenderer,
    InputHandler, and GameUI classes
  * Uses panel-based layout that prevents text overlap
  * Centralized configuration via UIConfig dataclass
  * Easier to extend and maintain
  * Drop-in compatible with original interface (run_pygame_ui())

All existing tests pass (25/25).

- Fix ui/pygame_ui.py text rendering:
  * Add boundary checking to _render_lines() to prevent overflow
  * Add max_y parameter to stop rendering before reaching another region
  * Add max_width parameter to truncate long lines with '...'
  * Status panel now bounded to Y=20-280
  * Event log now bounded to Y=300-580
  * Log entries dynamically limited based on available space

- Add PYGAME_OVERLAY_FIX.md documentation:
  * Explains the three root causes of text overlap
  * Provides three solution approaches (quick fix, panel-based, scrollable)
  * Includes before/after visual diagrams
  * Step-by-step instructions for each approach

All tests pass (25/25).