feat: add benchmark with ci

[xlc]

Summary of Changes:

• Introduces a new benchmark suite for core JAM components using the ordo-one/package-benchmark library.
• Adds a new JAMBenchmarks executable target to the JAMTests package to house the benchmarks.
• Implements benchmarks for several key areas based on W3F test vectors:
  • Erasure Coding (encode + reconstruct)
  • Shuffling
  • JamTestnet State Transition Function (STF) application
  • RecentHistory STF updates
• Creates a new BenchSupport.swift helper to expose test data from the JAMTests module to the external benchmark executable.
• Updates VS Code launch.json with configurations for running and debugging the benchmark suite.
• Adjusts visibility and concurrency conformance (public, Sendable) in JamTestnet.swift to allow its use in the benchmark target.

Highlights of Changed Code:

• JAMTests/Benchmarks/JAMBenchmarks/JAMBenchmarks.swift: New file containing all benchmark definitions.
• JAMTests/Package.swift: Addition of the package-benchmark dependency and the new JAMBenchmarks executable target.
• JAMTests/Sources/JAMTests/BenchSupport.swift: New public helper JAMBenchSupport for loading test data.
• JAMTests/Sources/JAMTests/JamTestnet.swift: runSTF is now public, and JamTestnetTestcase and related types are Sendable.
• .vscode/launch.json: Added "Debug JAMBenchmarks" and "Release JAMBenchmarks" configurations.
• Blockchain/Sources/Blockchain/RuntimeProtocols/Accumulation.swift: Minor stylistic refactor from closure-based flatMap to key-path expressions.

Additional Information:

• Testing: The new benchmarks can be executed using the Swift Package Manager (swift benchmark) or via the newly added VS Code launch configurations.

[github-actions]

The changes introduce a benchmark suite, which is a great addition. However, the implementation of the asynchronous benchmarks uses a custom, unsafe helper to block on async operations. This helper is unnecessary as the benchmarking library natively supports async/await, and its use should be replaced to improve code safety and simplicity.

[github-actions]

The changes introduce a new benchmark suite, which is a great addition. The implementation is mostly solid, but there's a potential for crashes in the benchmark executable due to force-unwrapping (try!) during test data decoding. This should be addressed to make the benchmarks more robust.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.75%. Comparing base (cfe98d5) to head (e9b7423).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #365      +/-   ##
==========================================
+ Coverage   81.64%   81.75%   +0.10%     
==========================================
  Files         381      381              
  Lines       33572    33572              
==========================================
+ Hits        27410    27446      +36     
+ Misses       6162     6126      -36     

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[github-actions]

The changes introduce a new benchmark suite, which is a great addition. However, there are a few issues to address. The primary issue is that one of the new benchmarks incorrectly includes data decoding time in its measurement, which will lead to inaccurate results. Additionally, there's a minor improvement to be made in the Swift package dependency declaration and a best-practice adjustment for a GitHub Action version.