B2.6: Dine-in - tables, QR, tabs, split checks, kitchen board

Part of #1. The Toast half.

• Table model with rotating qrToken; per-table QR (ts-qr-codes toSvg) -> menu with table context
• Tabs: open tab per table, multiple ordering rounds appended, running total
• Split checks: even split and by-item assignment; per-diner payment (sandbox Stripe), tip at close with tip-out recorded to the ledger
• Kitchen board: realtime channel for new rounds/orders per business; PrintDevice ticket dispatch
• Pickup-handoff QR on order confirmation (merchant scans to complete) and receipt -> review QR
• Tests: tab lifecycle, split math in cents (no lost pennies), QR token rotation

Live. Printable codes at https://smakelo.stacksjs.com/codes/marisol-cocina (six real ts-qr-codes SVGs, one per table), and scanning one opens /t/<token> which starts or joins that table's tab.

Verified: two rounds accumulate onto one tab, a second scan joins the same tab rather than starting a rival one, and $65.04 splits three ways as 2168 + 2168 + 2168 with no cent lost or invented.