test(devices): Phase 2 — ESC/POS byte stream + printer routing

Pins the device-layer bugs we kept hand-verifying, as pure byte-stream assertions
(no sockets, no hardware):

- printer-escpos.test.ts (12): CP852 codepage select; the ë→0x89 / Ë→0xD3 mapping
  and the em-dash/⚠ ASCII fallbacks (never a stray 0x3f "?"); and the Code128 MODULE
  WIDTH contract — a short ticket id at width 3, but the ~20-char out-of-window
  occurrence id at width 2 so it fits the 80mm head (width 3 overflows ~576 dots and
  the firmware silently aborts the barcode). Plus the QR-and-Code128 dual encoding and
  the Albanian stamp() format.
- printer-routing.test.ts (6): the failover order (booth printer is a fallback for
  entry tickets; a receipt never prints on the outside dispenser), rank-then-id
  tiebreak, and printWithFailover walking the order + NoPrinterAvailableError.

Wires Vitest into @parking/devices. devices 18/18 green.

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

packages/devices/tsconfig.json

@@ -7,5 +7,6 @@
     "types": ["node"]
   },
   "references": [{ "path": "../shared" }],
-  "include": ["src/**/*"]
+  "include": ["src/**/*"],
+  "exclude": ["src/**/*.test.ts"]
 }