fix: scrub automation output surfaces

[andrei-hasna]

Summary

• Scrub OpenLoops automation stdout/stderr/error and workflow event payloads before persistence and before public rendering.
• Add loops hygiene output-quarantine for historical output/event payload quarantine with dry-run default, forced backup on apply, and keyset pagination.
• Update MCP showOutput descriptions from raw to scrubbed output and add canary coverage for historical render, active workflow events, forced backup, and limited-batch scans.

Validation

• bun test src/lib/format.test.ts --timeout 30000
• bun test src/lib/store.test.ts --timeout 30000
• bun test src/lib/backup.test.ts --timeout 30000
• bun test src/cli/index.test.ts -t "hygiene output-quarantine" --timeout 30000
• bun test src/api/index.test.ts --timeout 30000
• bun test src/mcp/index.test.ts --timeout 30000
• LOOPS_UPDATE_GOLDEN=1 bun test src/mcp/golden-schema.test.ts --timeout 30000
• bun test src/cli/index.test.ts --timeout 60000
• bun run build
• git diff --check
• gitleaks protect --staged --redact --verbose
• gitleaks detect --redact --source . --log-opts HEAD~1..HEAD --verbose

Adversarial review

• Fixed pagination review finding by keyset-paginating quarantine scans and adding limit: 1 coverage.
• Fixed backup review finding by forcing a fresh backup for quarantine apply and adding repeated-apply coverage.
• Fixed active-event review finding by scanning all workflow event payload rows, including active workflow runs.
• Fixed render-path review finding by scrubbing all public structured payload string leaves before event/invocation/goal rendering.
• Final focused review reported no blockers for the public payload render fix.

Follow-ups

• Remaining owner surfaces are tracked as child tasks from T10: Codewith native/log watcher stores, dispatch/todos watcher surfaces, hooks env allowlist, and cross-package shared redaction contract rollout.