Admin Diagnose

Explain per-bot why an entry did or did not fire on the current tick.

Rebuilds one MarketSnapshot per universe, then runs every enabled bot's open_criteria inline and captures:

• The raw snapshot (spot, walls, GEX, regime, session progress).
• Whether the bot returned a signal — and if not, which gate rejected it, walked in the same order the bot uses at tick time.
• For any bot that DID emit a signal: whether spread_price would return a fillable per-share debit, which is the single biggest reason "signal fires but no trade is inserted." A missing or stale option_chains row for the ATM strike is the usual culprit.
• Scheduler status + when it last ticked (best-effort log-derived).

This endpoint is read-only — it never inserts a position or persists any state — so it is safe to hit repeatedly during diagnosis. Admin-scoped for consistency with the other /admin/* endpoints.