[John-David Dalton (jdalton)]

Make socket scan report readable in terminals and CI logs with a plain-text health summary and alert table.

Tests cover formatting and a 200,000-alert report. Continues #1601.

Automated review notes

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[!NOTE]
Low Risk
CLI report presentation only; JSON, Markdown, short output, and exit-code behavior are unchanged.

Overview
Default socket scan report text output no longer dumps the raw report object via logger.dir; it now renders a structured plain-text report with health status, aligned settings labels, and an alert table (URLs on separate lines).

Alert flattening is extracted into flattenReportAlerts and reused by both the new toPlainTextReport path and toMarkdownReport, so Markdown and text stay consistent. A new Vitest suite covers formatting (no ANSI/Map dumps, Unicode, column alignment, empty alerts, license/fold settings) and a 200k-alert regression to avoid argument-count failures when building large reports.

^{Reviewed by Cursor Bugbot for commit bf05dae. Configure here.}