Add the read-only planner and full-powers exec agent definitions for the
nextcloud-todos service (Phase 3, tasks 3.1/3.2). COPY both into
/usr/share/agent-seed/ so the seed-beads-agent init-container can drop them
into ~/.claude/agents/ at pod start (task 3.3).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
