docs(rtk): update RTK coverage from v0.16.0 to v0.28.0
New modules: docker compose, mypy, aws, psql, cargo nextest, Graphite CLI (gt), wc.
Major features: TOML Filter DSL (declarative filters, 33+ built-in, no Rust required),
rtk rewrite single source of truth (migration note: rtk init --global after upgrade),
rtk gain -p per-project savings, rtk init --global settings.json auto-patch,
exclude_commands config, SHA-256 hook integrity.
Updated: ultimate-guide.md, third-party-tools.md, reference.yaml (version_tested bump).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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