feat(validations): merchant (bar/lavazh) ticket validations end-to-end

In-park merchants discharge customers' parking: a merchant user scans the
ticket on their device (/validate; validation:create + program↔user binding)
and applies their program — comp / first-N-minutes free / amount-off (capped,
typed at scan) / percent. All money stays at the booth: the quote folds live
validations in a canonical order (timeCredit → percent → fixed → comp, net
floors at 0, Σ lines ≡ gross − net), the payment records gross/discount and
CONSUMES the validation ids (an overstay's fresh period never re-applies
them), the receipt prints the gross → lines → net story, and the Z/X-report
carries discountTotalMinor leakage. Every apply/void is a signed, attributed
ledger event (refId = append-only void); program config is /setup/site master
data (Bar/Lavazh checkboxes + right-column panel, tabs when both) whose saves
sign config_change. Migration 0024 + reset-db drift-guard entries; 8 route
integration tests + priceSession fold suite.

See wiki/concepts/validation-discounts.md for the full design record.

Claude-Session: https://claude.ai/code/session_01YYkpEsLmoQPaize5ec3oUm

packages/db/drizzle/meta/_journal.json

@@ -169,6 +169,13 @@
       "when": 1781886600000,
       "tag": "0023_driver_id_escpos",
       "breakpoints": true
+    },
+    {
+      "idx": 24,
+      "version": "6",
+      "when": 1783948800000,
+      "tag": "0024_validation_programs",
+      "breakpoints": true
     }
   ]
 }