feat(moonbit): add compact output filter for moon build/test/check

[colmugx]

Summary

• Add a new moon (MoonBit CLI) filter that auto-injects --output-json for build, test, and check, then parses the NDJSON diagnostics into compact Rust-compiler-style one-liners: path:line:col: level [code]: message.
• Only build/test/check are matched; other subcommands (run, new, clean, fmt, ...) pass through raw via the fallback path.
• Internal module is named moonbit (src/cmds/moonbit/moonbit_cmd.rs, Commands::Moonbit), while the proxied binary, CLI surface (rtk moon ...), and rewrite rule (^moon\s+(build|test|check)) all remain moon.

Test plan

• cargo fmt --all && cargo clippy --all-targets && cargo test — clippy clean, 2309 passed / 8 ignored
• Manual testing: rtk moon --help lists the subcommand; rtk rewrite moon build --target native → rtk moon build --target native; --output-json is injected at execution time and NDJSON diagnostics reformat correctly against real fixtures (22 unit tests)

Important: All PRs must target the develop branch (not master).
See CONTRIBUTING.md for details.

[CLAassistant]

All committers have signed the CLA.