guardrails: broader Claude asset migration beyond MVP floor

[terisuke]

Parent epic: #16

Problem

The MVP floor does not require full migration of every Claude-owned asset, but the longer-term product still needs a principled path for additional skills, commands, and packaging decisions.

Deliverables

• next-wave migration candidates beyond the MVP floor
• ownership rules for moving assets from .claude into .opencode
• packaging and maintenance rules for org-owned assets after the MVP ships

Acceptance

• the repo distinguishes MVP-critical migration from later migration work
• future asset moves can point to an explicit issue and ownership rule instead of ad hoc decisions

[terisuke]

Completed in Wave 9 (PR #134):

• Commands: 25/17 (100%+, 8 OC-exclusive)
• Agents: 31/26 (100%+, 5 OC-exclusive)
• Config: 8/8 (100%)
• Rules: ~100%
• Hooks: 56/56 applicable = 100% (guardrail.ts 1453 lines)

All Claude Code assets have been migrated to OpenCode guardrails plugin.