feat(setup): print a real test slip from the printer "Test connection" modal

healthCheck only opens the transport (TCP connect / USB open) — it proves the
printer is REACHABLE, not that paper feeds and the head fires. Add a "Print test
slip" action so the admin can physically confirm a printer is live (the new
host-net USB /dev/usb/lpN path, or a network printer).

- server: POST /api/setup/test-print — printer-only, re-merges stored secrets like
  /test (so an edited network printer authenticates), creates the device, and pushes
  a short slip via the device-agnostic printReport(). Fail-soft: a print error
  (paper out, head fault, transport drop) is reported, never a 500. Mirrors the
  test-anpr pattern.
- web: testPrint() client + PrintTestResult; a button in the device modal shown for
  category=printer, with ok/fail rendering. i18n keys in sq + en (parity holds).

Server 168 tests pass; web + server typecheck clean.

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

apps/server/src/routes/setup.ts

@@ -7,6 +7,7 @@ import {
   isCamera,
   isDiscoverable,
   isHardenable,
+  isPrinter,
   registerBuiltinDrivers,
   registry,
   setDeviceLogSink,
@@ -391,6 +392,70 @@ export async function setupRoutes(
     },
   );
 
+  // Print a TEST SLIP on a printer config WITHOUT saving. healthCheck only opens the
+  // transport (TCP connect / USB open) — it proves reachability, NOT that paper feeds
+  // and the head fires. This pushes a real short slip through the device-agnostic
+  // printReport(), so the admin can physically confirm the printer is live (the USB
+  // /dev/usb/lpN path or the network printer). Fail-soft like test-anpr: a print error
+  // is reported, never a 500. Mirrors /test's stored-secret re-merge so an edited
+  // network printer still authenticates.
+  app.post<{ Body: TestBody }>(
+    "/api/setup/test-print",
+    { preHandler: adminGuard },
+    async (req, reply) => {
+      const { driverId, config, id } = req.body;
+      const driver = registry.get(driverId);
+      if (!driver) return reply.code(400).send({ error: `unknown driver: ${driverId}` });
+      if (driver.category !== "printer") {
+        return reply.code(400).send({ error: `driver ${driverId} is not a printer` });
+      }
+
+      const merged: Record<string, string | number | boolean | undefined> = { ...config };
+      if (id) {
+        for (const [k, v] of Object.entries(storedSecrets(db, id, driverId, config))) {
+          const sent = merged[k];
+          if (sent === undefined || sent === "" || sent === 0) merged[k] = v as string | number;
+        }
+      }
+
+      let device;
+      try {
+        device = registry.create(driverId, merged as Record<string, string | number | boolean>);
+      } catch (err) {
+        return reply.code(400).send({ error: (err as Error).message });
+      }
+      if (!isPrinter(device)) {
+        return reply.code(400).send({ error: `driver ${driverId} cannot print` });
+      }
+
+      const startedAt = Date.now();
+      try {
+        await device.printReport({
+          title: "TEST PRINT",
+          lines: [
+            "Parking System",
+            "Printer test slip",
+            new Date().toLocaleString("sv"), // YYYY-MM-DD HH:MM:SS, locale-stable
+            "",
+            "If you can read this, the",
+            "printer is connected and",
+            "printing correctly.",
+          ],
+        });
+      } catch (err) {
+        // The failure we're testing for (paper out, head fault, transport drop) —
+        // report it, don't 500.
+        return reply.send({
+          ok: false,
+          reason: "print-failed",
+          detail: (err as Error).message,
+          tookMs: Date.now() - startedAt,
+        });
+      }
+      return reply.send({ ok: true, tookMs: Date.now() - startedAt });
+    },
+  );
+
   // Candidate backend IPs the device can push to, for a given device host. The
   // wizard pre-fills with the on-subnet one and lets the admin override (matters
   // on multi-NIC hosts). See net.ts / wiki/concepts/device-input-flow.md.

apps/web/src/SetupWizard.tsx

@@ -9,8 +9,10 @@ import {
   fetchState,
   testAnpr,
   testDevice,
+  testPrint,
   unassignDevice,
   type AnprTestResult,
+  type PrintTestResult,
   type Assignment,
   type BackendIpCandidate,
   type ButtonLightSpec,
@@ -339,6 +341,7 @@ function DeviceForm({
   const pushesToBackend = selected != null && pushCapableIds.includes(selected.id);
   const isController = category === "access";
   const isCamera = category === "camera";
+  const isPrinter = category === "printer";
   // ANPR opt-in for a camera: when true, the VisionReader polls this camera for plates
   // (config.anpr). Off by default. See wiki/entities/opencv-anpr-service.md.
   const [anpr, setAnpr] = useState<boolean>(editCfg?.anpr === true);
@@ -380,6 +383,10 @@ function DeviceForm({
   const [anprResult, setAnprResult] = useState<AnprTestResult | null>(null);
   const [anprTesting, setAnprTesting] = useState(false);
   const [anprError, setAnprError] = useState<string | null>(null);
+
+  const [printResult, setPrintResult] = useState<PrintTestResult | null>(null);
+  const [printTesting, setPrintTesting] = useState(false);
+  const [printError, setPrintError] = useState<string | null>(null);
   const [saving, setSaving] = useState(false);
   const [saveError, setSaveError] = useState<string | null>(null);
   const [found, setFound] = useState<DiscoveredDevice[] | null>(null);
@@ -531,6 +538,23 @@ function DeviceForm({
     }
   }
 
+  // Push a real test slip to the printer — proves it physically prints (healthCheck
+  // only opens the transport). Passes editing?.id so an edited network printer's
+  // stored secrets re-merge. Never blocks save.
+  async function testPrintNow() {
+    if (!selected) return;
+    setPrintTesting(true);
+    setPrintError(null);
+    setPrintResult(null);
+    try {
+      setPrintResult(await testPrint(selected.id, mergedScalarConfig(), editing?.id));
+    } catch (e) {
+      setPrintError((e as Error).message);
+    } finally {
+      setPrintTesting(false);
+    }
+  }
+
   async function save() {
     if (!selected) return;
     // Bound devices must point at a controller relay (binding is optional in the
@@ -867,6 +891,30 @@ function DeviceForm({
             </div>
           )}
 
+          {/* PRINTER: push a real test slip so the admin can confirm it physically
+              prints (healthCheck only opens the transport / USB node). */}
+          {isPrinter && (
+            <div className="mt-3 rounded-term border border-term-border bg-term-bg p-2">
+              <button type="button" className="btn btn-sm" onClick={testPrintNow} disabled={printTesting}>
+                {printTesting ? t("setup.printTesting") : t("setup.testPrint")}
+              </button>
+              <p className="hint mt-1">{t("setup.testPrintHint")}</p>
+
+              {printError && <p className="mt-2 text-[12px] text-term-red">{t("setup.testFailed", { error: printError })}</p>}
+              {printResult &&
+                (printResult.ok ? (
+                  <div className="mt-2 text-[12px] text-term-green">
+                    {t("setup.printOk", { ms: printResult.tookMs })}
+                  </div>
+                ) : (
+                  <div className="mt-2 text-[12px] text-term-amber">
+                    ⚠ {t(`setup.printFail.${printResult.reason}`, { defaultValue: printResult.reason })}
+                    {printResult.detail && <span className="text-term-muted"> — {printResult.detail}</span>}
+                  </div>
+                ))}
+            </div>
+          )}
+
           {backendIps && backendIps.length > 0 && (
             <div className="mt-3">
               <div className="field max-w-md">

apps/web/src/api.ts

@@ -350,6 +350,24 @@ export function testAnpr(driverId: string, config: DeviceConfig): Promise<AnprTe
   });
 }
 
+/** Result of a physical print test: a real test slip is pushed to the printer. */
+export type PrintTestResult =
+  | { ok: true; tookMs: number }
+  | { ok: false; reason: string; detail?: string; tookMs?: number };
+
+/** Print a real test slip on the printer — without saving. Confirms the printer
+ *  actually feeds paper + fires the head (healthCheck only opens the transport). */
+export function testPrint(
+  driverId: string,
+  config: DeviceConfig,
+  id?: string,
+): Promise<PrintTestResult> {
+  return apiFetch<PrintTestResult>("/api/setup/test-print", {
+    method: "POST",
+    body: JSON.stringify({ driverId, config, id }),
+  });
+}
+
 // --- Admin reports -------------------------------------------------------
 export type ReportBucket = "hour" | "day" | "month";
 

apps/web/src/lib/i18n/en.ts

@@ -406,6 +406,13 @@ export const en: Catalog = {
     "anprFail.vision-disabled": "Vision service is disabled — enable it (VISION_ENABLED) to test ANPR.",
     "anprFail.snapshot-failed": "Couldn't take a snapshot from the camera (offline or unreachable).",
     "anprFail.no-plate": "No plate found in the snapshot.",
+    // Printer test slip — pushes a real slip so the admin can confirm it physically prints.
+    testPrint: "Print test slip",
+    printTesting: "Printing…",
+    testPrintHint:
+      "Sends a test slip to the printer now. ‘Connected’ only opens the link — this confirms the printer actually feeds paper.",
+    printOk: "✓ Test slip sent ({{ms}} ms). Check the printer.",
+    "printFail.print-failed": "The printer rejected the job (out of paper, cover open, or the link dropped).",
     alarmUrlTitle: "Alarm Server settings (enter these in the camera)",
     alarmUrlHint:
       "Enter these in the camera at Configuration → Event → … → Alarm Settings (or Notify Surveillance Center). The camera POSTs every event here — no polling.",

apps/web/src/lib/i18n/sq.ts

@@ -416,6 +416,13 @@ export const sq = {
     "anprFail.vision-disabled": "Shërbimi i vizionit është çaktivizuar — aktivizoje (VISION_ENABLED) për ta testuar ANPR.",
     "anprFail.snapshot-failed": "Nuk u mor dot pamje nga kamera (jashtë linje ose e paarritshme).",
     "anprFail.no-plate": "Nuk u gjet asnjë targë në pamje.",
+    // Printer test slip — pushes a real slip so the admin can confirm it physically prints.
+    testPrint: "Printo provë",
+    printTesting: "Duke printuar…",
+    testPrintHint:
+      "Dërgon një fletë prove te printeri tani. ‘I lidhur’ vetëm hap lidhjen — kjo konfirmon se printeri vërtet nxjerr letër.",
+    printOk: "✓ Fleta e provës u dërgua ({{ms}} ms). Kontrollo printerin.",
+    "printFail.print-failed": "Printeri nuk pranoi punën (pa letër, kapaku hapur, ose lidhja ra).",
     // Alarm Server push settings — generated for the camera's Event → Alarm Server form.
     alarmUrlTitle: "Cilësimet e Alarm Server (vendosi te kamera)",
     alarmUrlHint: