parallel accumulate

[qiweiii]

• make it parallel (2% speed improve)
• remove pvm step logging (80% speed improve)

[codecov]

Codecov Report

❌ Patch coverage is 92.51337% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.66%. Comparing base (a66ce7c) to head (854a7c3).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...ces/Blockchain/RuntimeProtocols/Accumulation.swift	93.85%	11 Missing ⚠️
PolkaVM/Sources/PolkaVM/Engine.swift	50.00%	2 Missing ⚠️
...ain/Sources/Blockchain/State/ServiceAccounts.swift	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #361      +/-   ##
==========================================
+ Coverage   80.63%   80.66%   +0.03%     
==========================================
  Files         378      378              
  Lines       33216    33313      +97     
==========================================
+ Hits        26784    26873      +89     
- Misses       6432     6440       +8     

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[github-actions]

The changes introduce parallel processing to the accumulation logic, which is a significant architectural improvement. The implementation correctly uses task groups and handles state management across parallel tasks by batching services based on their dependencies. The removal of PVM step logging into a conditional flag is also a good performance optimization. One minor issue was found regarding removed documentation.

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Review Suggestions

Blockchain/Sources/Blockchain/RuntimeProtocols/Accumulation.swift:498-499

Two lines of comments describing the purpose of the update function were removed. While the code is the source of truth, comments that explain the high-level purpose of a complex function are valuable for future maintainers. Please consider restoring these comments.

[xlc]

Ideally we only access env from main file so this won't become a "hidden" setting. It also make it possible to toggle this value in different way under other context (e.g. in tests)