loadbearer v0.6.0

• New loadbearer score command. Re-score an existing result file against a
  different baseline, profile or curve without re-running the benchmarks — the
  file keeps every raw measurement, so the grade is just one view of it that can
  be recomputed in a second.
  • loadbearer score result.json --baseline our-fleet.toml scores against a
    baseline you built with loadbearer baseline; --profile and --curve-k
    override the values the file was scored with; --output writes a new
    result file; --json emits it to stdout.
  • A short banner shows what changed (baseline / profile / curve / tool
    version) and the old → new overall.
  • Subtests the baseline has no entry for are left out of the score with a
    note, rather than being a hard error — a fleet baseline that omits the
    OS-dependent network component is a normal thing to re-score against. The
    file's full raw is preserved in the output.
• Baseline::load reads a baseline TOML from a path (used by score --baseline).

Full Changelog: v0.5.1...v0.6.0