Fixes the second unsanitized exit point flagged in issue #413:
- task_id filter path: sanitize summary + response_preview before returning raw delegation object
- list path (all recent): sanitize both fields in every delegation entry before embedding in JSON
Both are peer-supplied delegation ledger data returned via the JSON polling endpoint.
Sync path (lines 173, 182) was already fixed in #416.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>