Fix use-after-free in geometry rendering by deferring eviction until
after rendering is complete:
- Add pending_eviction field to TileCache
- Add set_pending_eviction() method to schedule eviction
- Modify tick() to perform pending eviction at start of next frame
- Rename evict() to evict_internal() for deferred execution
- Update view.rs to call set_pending_eviction() instead of evict()
This prevents use-after-free by ensuring that Geometry objects are not
freed while the renderer is still using them. Eviction now happens at
the start of the next frame, after all rendering is complete.
Fixes: BUG-005 (Use-After-Free in Geometry Rendering)
Fix memory leak in cache eviction by explicitly freeing GPU resources
(Geometry objects) when tiles are evicted from the cache.
Changes:
- Add cx: &mut Cx parameter to evict() method
- Free fill_geometry and stroke_geometry before removing tiles
- Update all callers to pass cx parameter
- Update test code to create default Cx for tests
This prevents GPU memory leaks when tiles are evicted from the cache
during pan/zoom operations.
Fixes: BUG-002 (Memory Leak in Cache Eviction)
