fix(discovery): correct modern protocol status offset to 0x8A

Status code is at offset 0x8A, not 0x90. The old offset was reading
the LAN mode flag byte instead. Also corrects serial number field
size from 130 to 128 bytes to match actual packet layout.

Author: GhostTypes

src/api/PrinterDiscovery.test.ts

@@ -69,13 +69,13 @@ describe('PrinterDiscovery', () => {
         buffer.writeUInt16BE(commandPort, 0x84);
         buffer.writeUInt16BE(vendorId, 0x86);
         buffer.writeUInt16BE(productId, 0x88);
-        buffer.writeUInt16BE(productType, 0x8C);
-        buffer.writeUInt16BE(eventPort, 0x8E);
-        buffer.writeUInt16BE(statusCode, 0x90);
+        buffer.writeUInt16BE(statusCode, 0x8a);
+        buffer.writeUInt16BE(productType, 0x8c);
+        buffer.writeUInt16BE(eventPort, 0x8e);
 
         // Write serial number (UTF-8, null-terminated)
         buffer.write(serialNumber, 0x92, 'utf8');
-        buffer.fill(0, 0x92 + serialNumber.length, 0x92 + 130);
+        buffer.fill(0, 0x92 + serialNumber.length, 0x92 + 128);
 
         return buffer;
     };

src/api/PrinterDiscovery.ts

@@ -479,15 +479,17 @@ export class PrinterDiscovery {
     /**
      * Parses modern protocol (276-byte) discovery responses.
      *
-     * Modern protocol structure:
-     * - Printer name: 0x00, 132 bytes, UTF-8
+     * Modern protocol structure (276 bytes / 0x114):
+     * - Printer name: 0x00, 128 bytes, UTF-8 (+ 4 bytes padding at 0x80)
      * - Command port: 0x84, uint16 BE
      * - Vendor ID: 0x86, uint16 BE
      * - Product ID: 0x88, uint16 BE
+     * - Status code: 0x8A, uint16 BE
      * - Product type: 0x8C, uint16 BE
      * - Event port: 0x8E, uint16 BE
-     * - Status code: 0x90, uint16 BE
-     * - Serial number: 0x92, 130 bytes, UTF-8
+     * - LAN mode: 0x90, uint8 (0=cloud, 1=LAN-only)
+     * - Reserved: 0x91, uint8
+     * - Serial number: 0x92, 128 bytes, UTF-8 (+ 2 bytes padding)
      *
      * @param buffer The response buffer (276 bytes)
      * @param rinfo Remote address information
@@ -509,15 +511,15 @@ export class PrinterDiscovery {
         const commandPort = buffer.readUInt16BE(0x84);
         const vendorId = buffer.readUInt16BE(0x86);
         const productId = buffer.readUInt16BE(0x88);
-        const productType = buffer.readUInt16BE(0x8C);
-        const eventPort = buffer.readUInt16BE(0x8E);
+        const statusCode = buffer.readUInt16BE(0x8a);
+        const productType = buffer.readUInt16BE(0x8c);
+        const eventPort = buffer.readUInt16BE(0x8e);
 
         // Extract status
-        const statusCode = buffer.readUInt16BE(0x90);
         const status = this.mapStatusCode(statusCode);
 
         // Extract serial number (UTF-8, null-terminated)
-        const serialNumber = buffer.toString('utf8', 0x92, 0x92 + 130).replace(/\0.*$/, '');
+        const serialNumber = buffer.toString('utf8', 0x92, 0x92 + 128).replace(/\0.*$/, '');
 
         // Detect model
         const model = this.detectModernModel(name, productType);