fix: render concise task feedback

[Sandyzzx]

Summary

• Shorten long Agent summaries in the native task feedback renderer.
• Render shell-wrapped test commands as concise command labels without environment assignments or arbitrary arguments.
• Keep command-level results explicitly marked as Agent-reported; do not infer test-case counts from report details.
• Use singular/plural file counts and surface reported issues as compact warnings.
• Regenerate the marketplace bundle from the current 1.2.1 master baseline.

Validation

• npm run typecheck — passed
• npm run build — passed
• npm run validate:plugin — passed
• npm audit --omit=dev --audit-level=high — 0 production vulnerabilities
• npm test — running locally; CI will also run on this PR