feat(tcod): complete Dijkstra pathfinding implementation with critical PyArg fix

- Add complete Dijkstra pathfinding to UIGrid class
  - compute_dijkstra(), get_dijkstra_distance(), get_dijkstra_path()
  - Full TCODMap and TCODDijkstra integration
  - Proper memory management in constructors/destructors

- Create mcrfpy.libtcod submodule with Python bindings
  - dijkstra_compute(), dijkstra_get_distance(), dijkstra_get_path()
  - line() function for drawing corridors
  - Foundation for future FOV and pathfinding algorithms

- Fix critical PyArg bug in UIGridPoint color setter
  - PyObject_to_sfColor() now handles both Color objects and tuples
  - Prevents "SystemError: new style getargs format but argument is not a tuple"
  - Proper error handling and exception propagation

- Add comprehensive test suite
  - test_dijkstra_simple.py validates all pathfinding operations
  - dijkstra_test.py for headless testing with screenshots
  - dijkstra_interactive.py for full user interaction demos

- Consolidate and clean up test files
  - Removed 6 duplicate/broken demo attempts
  - Two clean versions: headless test + interactive demo

Part of TCOD integration sprint for RoguelikeDev Tutorial Event.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -27,3 +27,5 @@ forest_fire_CA.py
 mcrogueface.github.io
 scripts/
 test_*
+
+tcod_reference