feat(shift): cash drawer balance carried across shifts + admin cash movements

New signed cash_movement event (admin-only): load/remove drawer float, signed +
attributed. ShiftService folds cash payments + movements by time into a drawer
balance; shift open auto-inherits the prior shift's expected closing drawer as its
opening float; the Z-report reports opening/taken/added/removed/expected (= next
shift's opening float). Card payments excluded (settle to bank). Routes: POST
/api/cash-movement, drawer in GET /api/shift/current. ShiftControl shows the live
drawer + admin load/remove form + Z-report drawer block. Wiki: shift.md.

apps/server/src/routes/shift.ts

@@ -1,11 +1,19 @@
 import type { FastifyInstance } from "fastify";
 import { requireRole } from "../auth.js";
 import {
+  InvalidCashMovementError,
   NoOpenShiftError,
   ShiftAlreadyOpenError,
   type ShiftService,
 } from "../shift-service.js";
 
+interface CashMovementBody {
+  /** Signed minor units: positive = load INTO drawer, negative = remove FROM drawer. */
+  amountMinor: number;
+  reason?: string;
+  currency?: string;
+}
+
 // Shift endpoints (manned mode). The operator is the logged-in user; a shift is
 // opened/closed explicitly (not time-based — see wiki/concepts/shift.md and
 // local-jwt-auth.md "until logout"). End Shift signs a shift_z_report + prints it.
@@ -15,12 +23,36 @@ export async function shiftRoutes(app: FastifyInstance, shift: ShiftService): Pr
   const guard = requireRole("admin", "operator", "cashier");
 
   // Is the current operator's shift open? (For the UI to show Start vs. End.)
+  // Also returns the live drawer balance so the UI can show what's in the till.
   app.get("/api/shift/current", { preHandler: guard }, async (req) => {
     const operator = req.user.username;
     const open = shift.openShiftFor(operator);
-    return { operator, open: open ? { startedAt: open.occurredAt } : null };
+    const drawer = shift.drawerBalance();
+    return {
+      operator,
+      open: open ? { startedAt: open.occurredAt } : null,
+      drawerMinor: drawer.balanceMinor,
+      currency: drawer.currency,
+    };
   });
 
+  // Admin loads/removes physical drawer cash (the float). Signed cash_movement
+  // event. ADMIN ONLY — an operator takes payments but cannot move the float.
+  // amountMinor is signed: + load IN, − remove OUT. See wiki/concepts/shift.md.
+  app.post<{ Body: CashMovementBody }>(
+    "/api/cash-movement",
+    { preHandler: requireRole("admin") },
+    async (req, reply) => {
+      const { amountMinor, reason, currency } = req.body ?? ({} as CashMovementBody);
+      try {
+        return await shift.recordCashMovement(req.user.username, amountMinor, reason ?? "", currency);
+      } catch (err) {
+        if (err instanceof InvalidCashMovementError) return reply.code(400).send({ error: err.message });
+        return reply.code(500).send({ error: (err as Error).message });
+      }
+    },
+  );
+
   app.post("/api/shift/open", { preHandler: guard }, async (req, reply) => {
     try {
       return await shift.open(req.user.username);