Feature request: `/restart-session` command to reload skills and agents

When a skill or agent is updated (e.g. in .claude/skills/ or .claude/agents/), the current session doesn't pick up the changes — you have to exit and restart Claude Code entirely.

A /restart-session (or /reload) command would allow reloading skills, agents, and configuration without losing the conversation context.

Use case: During iterative development of custom skills and agents, having to restart the session each time is disruptive and loses conversation history.