chore: sync project state and current artifacts

tests/fluids/src/lib.rs

@@ -0,0 +1,9 @@
+//! Integration tests for the fluids backend.
+//!
+//! These tests verify cross-backend consistency, mixture handling,
+//! damping stability near the critical point, and cache integrity.
+
+pub mod backend_consistency;
+pub mod mixture_glide;
+pub mod damping_stability;
+pub mod cache_integrity;