chore(agents): add MQ dual skills bundle

[MCamner]

What

Installs the MQ dual Claude/Codex skills bundle for mq-agent and adds short routing snippets to the committed agent surfaces.

• 5 skills under both surfaces (byte-identical): .claude/skills/ (Claude Code) and .agents/skills/ (Codex) — mq-writing-plans, mq-worktree-safe, mq-subagent-driven-development, mq-interactive-command-design, mq-secrets-public-safe.
• Short ## MQ Skills routing section added to CLAUDE.md and AGENTS.md (routing only — no skill bodies duplicated).

Why these skills

Per the MQ repo matrix, mq-agent owns planning + workflow routing, so it gets the planning/worktree/execution/interactive/public-safe set.

Notes

• Skills come from mq-skillpack-dual-v2, sanitized: the public-safe / threat-model scan lines no longer embed private identifiers — they use portable placeholders (<your-username> / <your-hostname> / <location>).
• CLAUDE.md / AGENTS.md are generated from mqobsidian templates; the hand-added routing block is overwritten on next regeneration. Durable fix = add the block to the mqobsidian generator templates (follow-up).
• No runtime/application code changed.

Verification

• .claude/skills == .agents/skills (dual layout identical)
• Public-safe scan clean (only the skills' own scan patterns match — documentation)

🤖 Generated with Claude Code