- Delete unified_cache_simple.rs (695 lines of duplicated code)
- Delete unified_cache_minimal.rs (489 lines of duplicated code)
- Delete cache.rs (old implementation)
- Update vm-engine-jit/src/lib.rs to remove 'pub mod cache' declaration
This eliminates 1200+ lines of redundant code with >90% overlap with unified_cache.rs.
Keeps unified_cache.rs as the sole cache implementation.
Part of P0-01 cleanup task from implementation roadmap.