Major refactor of the perspective system to use entity references instead of indices:
- Replaced `int perspective` with `std::weak_ptr<UIEntity> perspective_entity`
- Added `bool perspective_enabled` flag for explicit control
- Direct entity assignment: `grid.perspective = player`
- Automatic cleanup when entity is destroyed (weak_ptr becomes invalid)
- No issues with collection reordering or entity removal
- PythonObjectCache integration preserves Python derived classes
API changes:
- Old: `grid.perspective = 0` (index), `-1` for omniscient
- New: `grid.perspective = entity` (object), `None` to clear
- New: `grid.perspective_enabled` controls rendering mode
Three rendering states:
1. `perspective_enabled = False`: Omniscient view (default)
2. `perspective_enabled = True` with valid entity: Entity's FOV
3. `perspective_enabled = True` with invalid entity: All black
Also includes:
- Part 3: Procedural dungeon generation with libtcod.line()
- Part 4: Field of view with entity perspective switching
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
