feat(tariff): V2 — legacy-parity pricing (time-of-day, category, seasonal, flat)

Bring the legacy ParkSQL2017 pricing BREADTH onto our engine while keeping
integer-minor-unit money + immutable signed versions (rejecting legacy's
float money / mutable rows). TariffStructure becomes a discriminated union:
V1 = the original bare ladder (UNCHANGED, verbatim algorithm, golden-
regression-tested against the live version); V2 = {version:2, tz, shared
knobs, defaultCard, windowedCards[]} where each card is flat OR a block
ladder and may be scoped by wall-clock hour window / day-of-week / date
range / vehicle category.

computeFeeV2 prices by stepping one increment at a time, advancing the
ladder by ELAPSED minutes (continuous) while selecting the active card by
WALL-CLOCK time in the version's FROZEN tz. Decisions: tz is a per-site
setting (site_config.timezone, default Europe/Tirane) stamped server-side
into each version on publish — never the host clock (reproducibility);
default-card cap governs a mixed day; precedence = specificity
(date>dow>hour) -> priority -> name (total, order-independent), validation
rejects ambiguous ties; category = a card FIELD, frozen in the signed
vehicle_entry payload (site_config.default_vehicle_category default), read
at both pricing call-sites.

Composer: default card front-and-centre (flat/ladder toggle), tiers under
an "Advanced" disclosure; emits BARE V1 when no tiers (back-compat). DB:
migrations 0005 (timezone) + 0006 (default_vehicle_category). Stood up
vitest in @parking/shared (was zero tests on the ledger-feeding fee fn);
36 tests incl. golden V1 regression, happy-hour/overnight/dow/flat/category/
cap edges, precedence shuffle-invariance, Europe/Tirane DST determinism,
validation matrix — all green. No event-chain change.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

packages/db/drizzle/0005_site_timezone.sql

@@ -0,0 +1 @@
+ALTER TABLE `site_config` ADD `timezone` text;

packages/db/drizzle/0006_site_default_category.sql

@@ -0,0 +1 @@
+ALTER TABLE `site_config` ADD `default_vehicle_category` text;

packages/db/drizzle/meta/_journal.json

@@ -36,6 +36,20 @@
       "when": 1781800000000,
       "tag": "0004_subscriptions_rename",
       "breakpoints": true
+    },
+    {
+      "idx": 5,
+      "version": "6",
+      "when": 1781884800000,
+      "tag": "0005_site_timezone",
+      "breakpoints": true
+    },
+    {
+      "idx": 6,
+      "version": "6",
+      "when": 1781884900000,
+      "tag": "0006_site_default_category",
+      "breakpoints": true
     }
   ]
 }

packages/db/src/schema.ts

@@ -171,6 +171,19 @@ export const siteConfig = sqliteTable("site_config", {
    *  own price and may differ. null = no site default set. See
    *  wiki/entities/subscription.md. */
   subscriptionMonthlyPriceMinor: integer("subscription_monthly_price_minor"),
+  /** IANA timezone the site operates in (e.g. "Europe/Tirane"). Used to evaluate a
+   *  tariff's wall-clock pricing windows (happy hour / night / seasonal). COPIED into
+   *  each published tariff version's structure.tz so the windows are frozen/immutable
+   *  per version — historical sessions reprice deterministically regardless of any
+   *  later config change. null/absent ⇒ default "Europe/Tirane" at publish time.
+   *  See wiki/concepts/tariff-time-tiers.md. */
+  timezone: text("timezone"),
+  /** Default vehicle/customer category assigned to a transient entry when none is
+   *  captured at the lane (every transient today). Operator policy — a plain car park
+   *  leaves it "default"; a mixed lot might set "car". Frozen into each vehicle_entry
+   *  payload so V2 category pricing reprices identically at exit. null ⇒ the shared
+   *  DEFAULT_VEHICLE_CATEGORY fallback. See wiki/concepts/tariff-time-tiers.md. */
+  defaultVehicleCategory: text("default_vehicle_category"),
   updatedAt: text("updated_at")
     .notNull()
     .default(sql`(current_timestamp)`),