refactor: world generation (#17)

* refactor: use TBB for concurrent hash maps and parallelize chunk processing

* fix: tbb link fail

* refactor(chunk): remove biome check for caves in rivers and oceans

* refactor(random): replace std distributions with custom implementations

Avoid overhead and platform-dependent behavior of `<random>` distributions by using direct engine operations and integer arithmetic. This ensures deterministic, cross-platform results and improves performance.

* refactor(generation): use chunk seed for cave and river paths

- Use per-chunk seed instead of global path_id for cave and river generation.
- Remove unused m_sum variables and m_path_id members.
- Clamp river yaw within 10 degrees of initial direction.
- Fix river radius interpolation (use t instead of 1-t).
- Lower sea level from 64 to 63.

include/Cubed/gameplay/chunk_generator.hpp

@@ -4,6 +4,7 @@
 #include "Cubed/gameplay/biome.hpp"
 #include "Cubed/gameplay/block.hpp"
 #include "Cubed/gameplay/builders/biome_builder.hpp"
+#include "Cubed/gameplay/path_point.hpp"
 #include "Cubed/tools/cubed_random.hpp"
 
 #include <atomic>
@@ -61,6 +62,9 @@ private:
     unsigned m_chunk_seed = 0;
 
     void make_biome_builder();
+    void
+    carve_worm(const std::vector<PathPoint>& points, const ChunkPos& chunk_pos,
+               std::function<void(int /*x*/, int /*y*/, int /*z*/)> on_hit);
 };
 
 } // namespace Cubed