Add mitata benchmark for recommended config linting

[NullVoxPopuli-ai-agent]

Summary

• Adds a benchmark suite using mitata that measures linting performance of the recommended config across small/medium/large .js, .gjs, and .gts fixture files
• Includes a CI workflow that runs on every PR, comparing the branch against master and posting a performance comparison comment with summary table and boxplots
• Provides local scripts (pnpm bench, pnpm bench:compare, pnpm bench:summary) for running benchmarks during development

Modeled after the benchmark infrastructure in ember-eslint-parser.

New files

Path	Purpose
tests/lint.bench.mjs	Main benchmark script using ESLint's Linter API + mitata
tests/bench/*.{js,gjs,gts}	Fixture files (small/medium/large) with realistic Ember code
scripts/bench-compare.mjs	Orchestrates control vs experiment comparison via git archive
scripts/bench-utils.mjs	Shared formatting utilities
scripts/format-bench-comment.mjs	Generates GitHub PR comment markdown
scripts/format-bench-cli.mjs	CLI-friendly summary table
scripts/run-bench.sh	CPU-pinned wrapper for local runs
scripts/local-bench-summary.sh	Full local comparison with CPU tuning tips
.github/workflows/bench-compare.yml	CI workflow for automatic PR benchmark comments

Test plan

• pnpm bench runs successfully and produces output
• Verify pnpm bench:compare works against master
• Open a PR and confirm the CI workflow posts a benchmark comment

🤖 Generated with Claude Code

[NullVoxPopuli]

looking good so far:

━━━ Summary ━━━

   Benchmark    Control (p50)   Experiment (p50)       Δ
   ──────────   ─────────────   ────────────────   ─────
⚪ js small           4.00 ms            3.95 ms   -1.3%
⚪ js medium          2.00 ms            2.02 ms   +1.0%
⚪ js large         822.04 µs          820.92 µs   -0.1%
⚪ gjs small        466.50 µs          461.96 µs   -1.0%
⚪ gjs medium       229.13 µs          230.92 µs   +0.8%
⚪ gjs large         92.67 µs           92.63 µs   -0.0%
⚪ gts small        456.54 µs          459.54 µs   +0.7%
⚪ gts medium       231.63 µs          229.13 µs   -1.1%
⚪ gts large         91.33 µs           92.08 µs   +0.8%

🟢 faster · 🔴 slower · 🟠 slightly slower · ⚪ within 2%

━━━ Tips for more reliable results ━━━