- Lava Business via gate.lava.ru (HMAC-SHA256 signed JSON requests)
- Sub-methods: card and SBP via includeService filter
- Webhook signature verified from raw bytes with secret_key_2
- Sticky terminal-status guard (success after amount_mismatch escalates to ERROR)
- Order ID with full uuid4 hex (128-bit entropy)
- Cross-row contamination guard: order_id assertion on invoice_id fallback
- Warning when hook URL cannot be derived from webhook/web_api/cabinet bases
- Explicit failure when Lava response lacks payment_url (no orphan rows)
- Adds LAVA settings category, /lava-webhook endpoint, cabinet topup branch
- Mirrors existing Antilopay/Jupiter/Donut mixin pattern