[Feature]: Audit current test coverage and identify coverage gaps

[me0106]

Is your feature request related to a problem? Please describe.
The project already has many modules and tests, but we do not currently have a clear repository-wide test coverage baseline. We need to understand the current coverage status and identify modules, packages, and critical paths that are not sufficiently protected by tests.

Describe the solution you'd like
Run a full test coverage audit for the current codebase and summarize the results.

Suggested scope:

• Run the current Maven/Jacoco coverage commands and generate coverage reports.
• Record the current overall coverage, including line coverage and branch coverage.
• Break down low-coverage areas by module, with special attention to core modules, server, plugin starters, and evaluation-related code.
• Identify critical business paths and auto-configuration paths that lack test coverage.
• Provide follow-up testing recommendations, including priority and reasonable coverage targets.
• Evaluate whether CI should enforce coverage checks or coverage thresholds.

Describe alternatives you've considered
A narrower audit could focus only on recently changed modules, but a repository-wide baseline is more useful as a long-term quality reference.

Additional context
Useful commands may include:

mvnd test
mvnd -Pcoverage-check verify

Expected output:

• Coverage report path or summary
• List of low-coverage modules
• Recommended areas to prioritize for additional tests
• Recommendation on whether to add CI coverage gates