Add CodSpeed performance benchmarks

[codspeed-hq]

Summary

This PR sets up continuous performance testing with CodSpeed for the repository.

Changes

• pytest-codspeed dependency: Added pytest-codspeed>=4.3.0 to the test dependency group for benchmark instrumentation.
• Benchmark suite (benchmarks/test_benchmarks.py): Created 8 benchmarks covering core algorithm implementations:
  • Sorting: bubble sort, heap sort, insertion sort, merge sort, quick sort, selection sort
  • Searching: binary search (iterative), binary search (recursive)
• CI workflow (.github/workflows/codspeed.yml): Added a GitHub Actions workflow that runs benchmarks on pushes to master, pull requests, and manual triggers. Uses OIDC authentication and simulation mode.
• README badge: Added a CodSpeed badge to the README.

How it works

CodSpeed instruments the benchmarks using CPU simulation to provide consistent, reproducible performance measurements regardless of CI runner hardware. This catches performance regressions automatically on every pull request.

Next steps

• Review the benchmark results on the CodSpeed dashboard once the first run completes.
• Consider adding more benchmarks for other algorithm categories (dynamic programming, graph algorithms, etc.) as needed.
• Performance checks can be enabled to block merging PRs that introduce regressions. See the CodSpeed docs for details.

[codspeed-hq]

Congrats! CodSpeed is installed 🎉

🆕 8 new benchmarks were detected.

You will start to see performance impacts in the reports once the benchmarks are run from your default branch.

Detected benchmarks

• test_insertion_sort: 24 ms
• test_merge_sort: 97.4 ms
• test_heap_sort: 72.5 ms
• test_binary_search_recursive: 3.6 ms
• test_bubble_sort: 40.1 ms
• test_selection_sort: 22.1 ms
• test_quick_sort: 35 ms
• test_binary_search: 3.6 ms

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