feat(tariff-lab): DB-backed draft tariffs + named published versions

Experimenting used to mean publishing — churning the immutable version
history and risking real tickets pricing against a half-baked card while
the admin iterated. The lab is now a true sandbox:

- tariff_drafts table (migration 0021): MUTABLE by design — the one
  exception to "editing publishes a version"; a draft prices nothing and
  signs nothing. Drafts are validated + tz-stamped on save exactly like a
  publish, so a saved draft always simulates and never fails at publish.
- CRUD under /api/tariff/drafts (list tariff:read, mutations
  tariff:update); publishing a draft goes through the normal immutable
  POST /api/tariff/versions path.
- Lab UI rebuilt: sidebar lists lab drafts AND the full published history
  (click any to price against it); main pane cut to pure entry/exit
  (ticket loader, payment, category inputs dropped); the composer form is
  extracted to TariffEditorForm.tsx and reused in a modal (new drafts
  prefill from the active card); per-draft Publish with confirm.
- tariff_versions.name (migration 0022): optional label stamped at
  publish — carried from the lab draft, or typed in the composer's new
  optional field — so history reads "Winter 2027", not UUID prefixes.
- Includes the composer UI + sq/en labels for the package mode (engine
  landed in d9e6c13) and the "Flat price / hour" relabel.

5 new server integration tests (RBAC, roundtrip, validation, tz-stamp +
simulate + publish w/ name); server suite 288 green.

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

apps/web/src/api.ts

@@ -669,10 +669,14 @@ export interface TariffCard {
   priority: number;
   category?: string;
   window?: TariffWindow;
+  /** Flat price PER INCREMENT (an hourly flat rate) — not a whole-stay price. */
   flatMinor?: number;
   blocks?: TariffBlock[];
   /** STEPPED ("up-to") table (defaultCard only); mutually exclusive with flat/blocks. */
   steps?: TariffStep[];
+  /** WINDOW PACKAGE (windowed cards only): ONE total per contiguous window occurrence
+   *  ("any presence in the window = this price"). Mirrors @parking/shared. */
+  packageMinor?: number;
   dailyCapMinor?: number | null;
 }
 /** One row of a STEPPED ("up-to") tariff: a TOTAL price for a stay up to and including
@@ -702,6 +706,8 @@ export function isTariffV2(t: TariffStructure): t is TariffStructureV2 {
 export interface TariffVersion {
   id: string;
   tariffId: string;
+  /** Optional human label, stamped at publish (e.g. carried from a lab draft). */
+  name?: string | null;
   effectiveFrom: string;
   currency: string;
   structure: TariffStructure;
@@ -723,6 +729,7 @@ export function publishTariffVersion(body: {
   currency: string;
   structure: TariffStructure;
   effectiveFrom?: string;
+  name?: string;
 }): Promise<TariffVersion> {
   return apiFetch("/api/tariff/versions", { method: "POST", body: JSON.stringify(body) });
 }
@@ -761,18 +768,40 @@ export function simulateTariff(body: SimulateBody): Promise<SimulateResult> {
   return apiFetch("/api/tariff/simulate", { method: "POST", body: JSON.stringify(body) });
 }
 
-export interface SimSessionLoad {
-  identity: string;
-  enteredAt: string;
-  exitedAt: string | null;
-  payments: SimPayment[];
-  category: string | null;
-  tariffVersionId: string | null;
+// --- Tariff Lab drafts ------------------------------------------------------
+// Mutable experimental rate cards — the lab composes + simulates these, and
+// publishing one goes through the normal immutable-version path above.
+
+export interface TariffDraft {
+  id: string;
+  name: string;
+  currency: string;
+  structure: TariffStructure;
+  createdBy: string | null;
+  createdAt: string;
+  updatedAt: string;
 }
 
-/** Prefill the lab from a real ledger session. */
-export function loadSimSession(identity: string): Promise<SimSessionLoad> {
-  return apiFetch(`/api/tariff/simulate/session/${encodeURIComponent(identity)}`);
+export function fetchTariffDrafts(): Promise<{ drafts: TariffDraft[] }> {
+  return apiFetch("/api/tariff/drafts");
+}
+
+export interface TariffDraftBody {
+  name: string;
+  currency: string;
+  structure: TariffStructure;
+}
+
+export function createTariffDraft(body: TariffDraftBody): Promise<TariffDraft> {
+  return apiFetch("/api/tariff/drafts", { method: "POST", body: JSON.stringify(body) });
+}
+
+export function updateTariffDraft(id: string, body: TariffDraftBody): Promise<TariffDraft> {
+  return apiFetch(`/api/tariff/drafts/${encodeURIComponent(id)}`, { method: "PUT", body: JSON.stringify(body) });
+}
+
+export function deleteTariffDraft(id: string): Promise<void> {
+  return apiFetch(`/api/tariff/drafts/${encodeURIComponent(id)}`, { method: "DELETE" });
 }
 
 // --- Subscriptions --------------------------------------------------------