feat: dagrunner, initial version

tests/boundaries/mod.rs

@@ -0,0 +1,9 @@
+//! Boundary and edge case tests for dagx
+//!
+//! Tests extreme values, limits, and edge cases that might not be covered
+//! by normal usage patterns.
+
+mod deep_chains;
+mod large_scale;
+mod type_limits;
+mod zero_tasks;