feat(dev): add pre-launch hooks

[basnijholt]

Summary

• add built-in launch preparation plus configurable pre_launch hooks for dev new and dev agent
• seed Codex trust for the launched worktree path before headless starts and allow --no-hooks to bypass preparation
• make runtime dev config resolution respect --config, update docs/skills, and add regression coverage

Verification

• pytest tests/dev/test_cli.py tests/dev/test_coding_agents.py tests/dev/test_hooks.py tests/dev/test_launch.py tests/dev/test_terminals.py -q
• pre-commit run --files agent_cli/dev/skill/SKILL.md agent_cli/dev/skill/examples.md .claude-plugin/skills/agent-cli-dev/SKILL.md .claude-plugin/skills/agent-cli-dev/examples.md .claude/skills/agent-cli-dev/SKILL.md .claude/skills/agent-cli-dev/examples.md docs/commands/dev.md agent_cli/cli.py agent_cli/dev/_config.py agent_cli/dev/cli.py agent_cli/dev/coding_agents/base.py agent_cli/dev/coding_agents/codex.py agent_cli/dev/hooks.py agent_cli/dev/launch.py tests/dev/test_cli.py tests/dev/test_coding_agents.py tests/dev/test_hooks.py
• markdown-code-runner docs/commands/dev.md