[Sync] Update project files from source repository (c5b3708)

[mrz1836]

What Changed

• Updated MAGE_X_VERSION from v1.15.0 to v1.15.5 in .github/.env.base
• Updated MAGE_X_GOLANGCI_LINT_VERSION from v2.7.2 to v2.8.0 in .github/.env.base
• Updated GO_PRE_COMMIT_GOLANGCI_LINT_VERSION from v2.7.2 to v2.8.0 in .github/.env.base
• Added parsing of new size metrics in fortress-completion-statistics.yml workflow including test file sizes, Go file sizes, total size, and average size bytes for both test and Go files
• Added parsing of new code quality metrics including average lines per file, test coverage ratio, and package count

Why It Was Necessary

• Upgrading MAGE-X to latest version (v1.15.5) ensures access to recent bug fixes and improvements
• Upgrading golangci-lint to v2.8.0 provides latest linting rules and bug fixes for both CI and pre-commit hooks
• Enhanced metrics collection enables better visibility into codebase size characteristics and code quality indicators for fortress completion tracking

Testing Performed

• Verified that the new environment variable values are syntactically correct and reference valid tool versions
• Confirmed that the new JSON parsing statements in the workflow align with expected output fields from the LOC analysis tool
• Validated that existing workflow logic remains intact and the new metric variables are parsed but not yet utilized in downstream steps

Impact / Risk

• Low Risk: Version bumps are minor/patch updates that maintain backward compatibility
• No Breaking Changes: New metrics are additive only and do not modify existing workflow behavior
• CI Impact: Workflow will parse additional metrics from LOC output but existing functionality remains unchanged

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud