feat(adminui): add DriverFormShell shared component

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Shared/Drivers/DriverFormShell.razor

@@ -0,0 +1,34 @@
+@* Shared shell for driver edit/new pages — panel layout + Save/Cancel/Delete bar + error banner.
+   The parent page owns the <EditForm> — this shell only renders the button bar. *@
+
+<div>
+    @ChildContent
+
+    @if (!string.IsNullOrWhiteSpace(Error))
+    {
+        <div class="panel notice mt-3" style="border-color:var(--alert)">@Error</div>
+    }
+
+    <div class="mt-3 d-flex gap-2">
+        <button type="submit" class="btn btn-primary" disabled="@Busy">
+            @if (Busy) { <span class="spinner-border spinner-border-sm me-1"></span> }
+            @(IsNew ? "Create" : "Save changes")
+        </button>
+        <a href="@CancelHref" class="btn btn-outline-secondary">Cancel</a>
+        @if (OnDelete.HasValue)
+        {
+            <button type="button" class="btn btn-outline-danger ms-auto" @onclick="OnDelete.Value" disabled="@Busy">
+                Delete
+            </button>
+        }
+    </div>
+</div>
+
+@code {
+    [Parameter] public bool IsNew { get; set; }
+    [Parameter] public bool Busy { get; set; }
+    [Parameter] public string? Error { get; set; }
+    [Parameter, EditorRequired] public string CancelHref { get; set; } = "";
+    [Parameter] public EventCallback? OnDelete { get; set; }
+    [Parameter] public RenderFragment? ChildContent { get; set; }
+}