Enforce canonical Wave library dependencies

[LunaStev]

Summary

• require Wave dependencies to declare lib = true and provide the canonical src/lib.wave package root
• preserve direct and transitive dependency mappings passed to wavec for import("package") and import("package::module")
• document the package-to-module contract and expand CLI, resolver, lockfile, and compiler-argument coverage

Validation

• cargo fmt --all --check
• cargo check --locked --jobs 2
• cargo test --locked --jobs 2 (32 tests passed)
• cargo clippy --locked --all-targets --jobs 2 -- -D warnings
• git diff --check
• path and local Git dependency end-to-end checks against the companion Wave import-system branch

Companion change

• Complete the Wave module import system Wave#344 implements and tests the matching compiler module system.