feat(guardrails): remaining 5 CC agent definitions to OC

[terisuke]

Summary

Migrate remaining 5 Claude Code agent definitions to OpenCode guardrails profile.

Previous state: 14 agents were tracked here. PRs #113 and #114 merged all 14.
Current state: 26 OC agents exist, but 5 CC agents still have no OC equivalent.

Agents to Add (5)

Agent	CC Role	OC Alternative	Priority
code-reviewer	Expert code review (quality, security, maintainability)	review subagent (partial)	Medium
database-administrator	DB admin (install, config, perf, HA, backup, replication)	database-optimizer (partial)	Medium
mobile-developer	Cross-platform mobile (React Native, Flutter)	None	Low
refactor-cleaner	Dead code cleanup, consolidation (knip, depcheck, ts-prune)	/refactor-clean command (partial)	Low
security-reviewer	Security vulnerability detection (OWASP Top 10, secrets)	security + security-engineer (partial)	Medium

Permission Considerations

• code-reviewer: Read-only — no edit/write/bash needed
• database-administrator: Needs bash for DB CLI tools, deny destructive ops
• mobile-developer: Standard implement-like permissions
• refactor-cleaner: Needs edit/write + bash for analysis tools, deny rm -rf
• security-reviewer: Read-only + bash for scanning, deny secret file reads

Ref

Master Plan #51, Gap analysis report, PR #113, PR #114