Set up benchmarks with AirspeedVelocity.jl

[Krastanov]

Summary

• Remove broken BenchmarkCI workflows that weren't working
• Add benchmark suite for traversal operations using BenchmarkTools.jl
• Set up AirspeedVelocity.jl CI workflow to run benchmarks on PRs
• Update CLAUDE.md with benchmark documentation and guidelines

Benchmark coverage

Current benchmarks cover the traversal function:

• Swap traversal (different circuit sizes: 10, 100, 1000)
• No-op traversal (visiting without changes)
• Combine traversal (reducing circuit by merging operations)
• Mixed circuits with different gate types
• Direction comparison (left vs right traversal)

Test plan

• Verified benchmarks run locally with julia -tauto --project=benchmark -e 'include("benchmark/benchmarks.jl"); run(SUITE)'
• CI workflow will run on this PR to verify AirspeedVelocity setup

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.60%. Comparing base (2fc7840) to head (e553bf9).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master       #6   +/-   ##
=======================================
  Coverage   78.60%   78.60%           
=======================================
  Files           4        4           
  Lines         187      187           
=======================================
  Hits          147      147           
  Misses         40       40           

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