release: v0.17.12

[edwin-zvs]

Summary

• bump the workspace version to 0.17.12
• update Cargo.lock workspace package versions
• point the Homebrew formula at v0.17.12 (checksums will be updated after release artifacts publish)

Verification

• cargo build
• ./target/debug/construct --version
• brew style Formula/construct.rb
• git diff --check

Note

• cargo fmt --all -- --check reports pre-existing formatting drift in unrelated source files; this PR does not modify those files.