Auto: focas-f4d — password / unlock parameter

Closes #271

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FwlibNative.cs

@@ -66,6 +66,25 @@ internal static class FwlibNative
         short length,
         ref IODBPSD buffer);
 
+    /// <summary>
+    ///     <c>cnc_wrunlockparam</c> — emit the connection-level password that lifts
+    ///     the parameter-protect / read-protect gate on certain firmwares (issue #271,
+    ///     plan PR F4-d). The Fanuc FOCAS reference describes the password buffer as
+    ///     a 4-byte binary array (the controller compares byte-for-byte). Returns the
+    ///     usual <c>EW_*</c> family — <c>EW_PASSWD</c> when the supplied bytes don't
+    ///     match the configured password.
+    /// </summary>
+    /// <remarks>
+    ///     <para>P/Invoke shape kept narrow: the caller passes a 4-byte buffer. The
+    ///     driver layer ASCII-encodes <c>FocasDeviceOptions.Password</c> into the
+    ///     buffer (right-padded with <c>0x00</c>, truncated to 4 bytes) — that's the
+    ///     shape every public Fanuc password example we've seen uses.</para>
+    /// </remarks>
+    [DllImport(Library, EntryPoint = "cnc_wrunlockparam", ExactSpelling = true)]
+    public static extern short WrUnlockParam(
+        ushort handle,
+        [In] byte[] password);
+
     // ---- Macro variables ----
 
     [DllImport(Library, EntryPoint = "cnc_rdmacro", ExactSpelling = true)]