wad_builder 1.0.0

Mercenaries 2 modernization — generic raw-asset to engine-format vz-patch.wad builder, with a byte-exact identity oracle for parse/serialize correctness.
wad_builder-1.0.0 is not a library.

wad_builder — generic "raw asset → engine format → vz-patch.wad" builder.

Jumping off from dlc_port/cube_mod, this crate adds the build-side editing those lack: replacing a Lua script inside a multi-entry scripts_vz block (compile-from-source → re-wrap BINN/UCFX → fix CSUM + chunk_size).

identity-test is the correctness oracle: it proves the parse/serialize and CSUM model reproduce a real block byte-for-byte before any edit is applied.