shorten block time to 0.5 seconds

[alstjd0921]

Description

• shorten block time to 0.5 seconds

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Something else (simple changes that are not related to existing functionality or others)

Checklist

• I have selected the correct base branch.
• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have made new test codes regarding to my changes.
• I have no personal secrets or credentials described on my changes.
• I have run cargo-clippy and linted my code.
• My changes generate no new warnings.
• My changes passed the existing test codes.
• My changes are able to compile.

[Copilot]

Pull Request Overview

Shortens the configured block production interval to 500ms to achieve faster block times.

• Update: MILLISECS_PER_BLOCK reduced from 3000 to 500.
• No accompanying documentation or derived constant adjustments are shown in this diff.

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