feat: re-model drawer cash as directional vouchers (Mandat Arkëtimi / Pagese)

Replace the single signed-± cash_movement with two distinct financial
documents — the direction is the event TYPE, not the sign of an amount:

  cash_in  = Mandat Arkëtimi (receipt / pay-IN,  +)  voucher AR-NNNN
  cash_out = Mandat Pagese  (disbursement / pay-OUT, −)  voucher PA-NNNN

Each carries a positive magnitude, voucher number, reason, the operator who
raised it and the admin who authorized it, and prints an Albanian slip.

Authorization changes from admin-only to operator-RAISED / admin-AUTHORIZED:
any shift:create holder raises the voucher, but POST /api/cash-voucher only
commits when authorizedBy is a real admin (shift:cash) re-entering their
password (verified server-side). Keeps the float control while letting the
operator do the booth paperwork.

Legacy cash_movement events are kept — they still verify and still fold into
the drawer (signed-±); the append-only chain is never rewritten. The drawer
fold and the Z-report window now sum all three types.

Verified against a copy of the live DB with the real signing modules:
cash_in 3000 + cash_out 5000 → drawer −2000, hash-chain verifies OK.

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

apps/web/src/BoothScreen.tsx

@@ -31,6 +31,8 @@ const EVENT_STYLE: Record<string, { labelKey: string; color: string }> = {
   shift_open: { labelKey: "booth.evtShiftOpen", color: "text-term-amber" },
   shift_z_report: { labelKey: "booth.evtShiftZ", color: "text-term-amber" },
   cash_movement: { labelKey: "booth.evtCashMovement", color: "text-term-cyan" },
+  cash_in: { labelKey: "booth.evtCashIn", color: "text-term-green" },
+  cash_out: { labelKey: "booth.evtCashOut", color: "text-term-amber" },
   anomaly: { labelKey: "booth.evtAnomaly", color: "text-term-red" },
 };