Upgrade Venom with Optimizations and Enhanced Error Handling

v0.4.1b4 upgrades venom with test machinery, load elimination, codesize optimization, and dload instruction propagation. It adds alphanumeric variables, compiles .vyi files, and improves error messages. Fixes block absolute relative imports, IERC4626 signatures, store elimination, and metadata functions. Codegen gains profiling utils. Docs clarify internal function behavior and ABI default argument signatures.