Fix CLI test summary accounting and exit status

[mikehorgan-dell]

Summary

• count only named final Go test events, including named parents and subtests
• exclude package completion events from test totals, percentages, and package breakdowns
• report package and build failures separately with captured compiler output
• measure and persist actual go test wall-clock duration for parse-only summaries
• preserve the original go test status through the progress pipeline and return it after rendering the summary
• clear stale failure reports and duration metadata before each run

Old versus corrected semantics

Previously every pass, fail, and skip event was counted as a test, including null-Test package events, and Duration summed overlapping test, subtest, parent, and package elapsed values. Pipeline consumers could also hide a nonzero go test status.

Now only final events with a non-null Test field count as individual executions. Package/build failures are reported separately, duration is measured around go test, and the original go test status is returned after the summary is displayed.