diagnose

Run a diagnosis on the current session: ```bash cozempic current --diagnose ``` The output includes: - **Weight**: total session size in bytes and message count - **Tokens**: exact token count (from usage data) or heuristic estimate - **Context bar**: visual bar showing % of the detected context window (200K or 1M) - **Vital signs**: progress ticks, file history snapshots, system reminders, thinking content, signatures, tool results - **Message type breakdown**: bytes per message type - **Top 10 largest messages**: biggest bloat contributors - **Estimated savings by prescription**: what gentle/standard/aggressive would save Always surface the token count and context % to the user. If context is above 60%, suggest running `/cozempic:treat` with a prescription recommendation: - Under 5MB: `gentle` - 5-20MB: `standard` - Over 20MB: `aggressive`