Replace raw JSON-RPC app-server protocol with @openai/codex-sdk.
The SDK wraps `codex exec` which ensures complete task execution per
turn, fixing the issue where app-server mode ended turns prematurely
(agent saying "하겠습니다" without doing the work).
Also fix AGENTS.md copy in agent-runner (was copying instructions.md
which Codex CLI doesn't read).
- Add Codex as alternative agent type (agentType: 'codex' per group)
- Codex container runner with session resume and 100-turn limit
- Dual Discord bot support (DISCORD_BOT_TOKEN + DISCORD_CODEX_BOT_TOKEN)
- Each bot handles only its agentType's registered groups
- Discord typing indicator refreshes every 8s (was single-shot, expired after ~10s)
- Agent runner 100-turn limit to prevent infinite bot-to-bot loops
- Apple Container runtime support (convert-to-apple-container skill)
- Session commands (/compact) support
- DB migration for agent_type column
