Add decode parity test and gate Server engine option on availability

app/proprietary/src/main/java/stirling/software/proprietary/formdetection/model/ModelStatusResponse.java

@@ -40,4 +40,7 @@ public class ModelStatusResponse {
 
     /** Where detection runs: auto | browser | server. */
     private String executionMode;
+
+    /** True if the server-side ONNX engine is bundled in this build (else only browser works). */
+    private boolean serverEngineAvailable;
 }

app/proprietary/src/main/java/stirling/software/proprietary/formdetection/service/FormDetectionModelManager.java

@@ -59,6 +59,25 @@ public class FormDetectionModelManager {
     private static final Pattern SAFE_ID = Pattern.compile("[a-z0-9][a-z0-9-]{0,63}");
     private static final Pattern SHA256_HEX = Pattern.compile("[0-9a-f]{64}");
 
+    /**
+     * Whether the server-side ONNX engine is bundled in this build (the onnxruntime jar is only
+     * included via {@code -PbundleOnnxRuntime=true}, e.g. the Docker server image). The frontend
+     * uses this to disable the "Server" execution mode when it isn't available.
+     */
+    private static final boolean SERVER_ENGINE_AVAILABLE = isOnnxRuntimePresent();
+
+    private static boolean isOnnxRuntimePresent() {
+        try {
+            Class.forName(
+                    "ai.onnxruntime.OrtEnvironment",
+                    false,
+                    FormDetectionModelManager.class.getClassLoader());
+            return true;
+        } catch (Throwable t) {
+            return false;
+        }
+    }
+
     private final RuntimePathConfig runtimePathConfig;
     private final ModelCatalogService catalog;
     private final ApplicationProperties applicationProperties;
@@ -363,7 +382,8 @@ public class FormDetectionModelManager {
                 isWritable(dir),
                 catalog.getAll(),
                 isFeatureEnabled(),
-                applicationProperties.getFormDetection().getExecutionMode());
+                applicationProperties.getFormDetection().getExecutionMode(),
+                SERVER_ENGINE_AVAILABLE);
     }
 
     public Optional<Path> getActiveModelFile() {

app/proprietary/src/test/java/stirling/software/proprietary/formdetection/controller/FormDetectionModelControllerTest.java

@@ -21,7 +21,7 @@ class FormDetectionModelControllerTest {
 
     private ModelStatusResponse notInstalled() {
         return new ModelStatusResponse(
-                "not_installed", 0, "", List.of(), null, true, List.of(), true, "auto");
+                "not_installed", 0, "", List.of(), null, true, List.of(), true, "auto", true);
     }
 
     private MockMvc mvc(FormDetectionModelManager manager) {

frontend/editor/src/core/hooks/useFormDetectionModelStatus.ts

@@ -45,6 +45,7 @@ export interface FormDetectionModelStatus {
   catalog: FormDetectionCatalogEntry[];
   enabled: boolean;
   executionMode: FormDetectionExecutionMode;
+  serverEngineAvailable: boolean;
 }
 
 const STATUS_URL = "/api/v1/ai/form-detection-model/status";

frontend/editor/src/core/services/formDetection/decode.test.ts

@@ -0,0 +1,78 @@
+import { describe, it, expect } from "vitest";
+
+import { decode } from "@app/services/formDetection/decode";
+import {
+  ModelPipelineSpec,
+  Preprocessed,
+  RawOutput,
+} from "@app/services/formDetection/types";
+
+// Golden fixture shared VERBATIM with the backend YoloTest.java
+// (decodeThresholdsAndSuppressesOverlaps). Asserting the same inputs -> same outputs in both
+// suites proves the in-browser decode matches the server decode 1:1, so the two execution paths
+// produce identical detections.
+
+const spec: ModelPipelineSpec = {
+  inputSize: 10,
+  resizeMode: "letterbox",
+  padColor: [114, 114, 114],
+  channelOrder: "rgb",
+  normMean: [0, 0, 0],
+  normStd: [1, 1, 1],
+  outputLayout: "nc_first",
+  hasObjectness: false,
+  classNames: ["text", "choice"],
+  classFieldTypes: ["text", "checkbox"],
+  scoreThreshold: 0.5,
+  nms: "perClass",
+  iou: 0.5,
+};
+
+// identity transform (scale 1, no pad), 10x10 source
+const pre: Preprocessed = {
+  chw: new Float32Array(0),
+  inputSize: 10,
+  scaleX: 1,
+  scaleY: 1,
+  padX: 0,
+  padY: 0,
+  srcW: 10,
+  srcH: 10,
+};
+
+// nc_first layout [channels=6][anchors=3], data[c*anchors + a]
+// box A (cx5,cy5,w4,h4) twice (overlapping) + box B (cx8,cy8,w2,h2)
+const data = [
+  5, 5, 8, // cx
+  5, 5, 8, // cy
+  4, 4, 2, // w
+  4, 4, 2, // h
+  0.9, 0.8, 0.7, // text score
+  0.1, 0.1, 0.1, // choice score
+];
+const out: RawOutput = { data, d1: 6, d2: 3 };
+
+describe("formDetection decode (parity with backend Yolo.decode)", () => {
+  it("thresholds and suppresses overlaps identically to the Java golden fixture", () => {
+    const dets = decode(out, spec, pre, 0.5);
+    // a0 (box A, 0.9) kept; a1 (box A', 0.8) suppressed by NMS; a2 (box B, 0.7) kept
+    expect(dets).toHaveLength(2);
+
+    expect(dets[0].classId).toBe(0);
+    expect(dets[0].score).toBeCloseTo(0.9, 5);
+    expect(dets[0].x).toBeCloseTo(3, 4);
+    expect(dets[0].y).toBeCloseTo(3, 4);
+    expect(dets[0].w).toBeCloseTo(4, 4);
+    expect(dets[0].h).toBeCloseTo(4, 4);
+
+    expect(dets[1].score).toBeCloseTo(0.7, 5);
+    expect(dets[1].x).toBeCloseTo(7, 4);
+    expect(dets[1].y).toBeCloseTo(7, 4);
+    expect(dets[1].w).toBeCloseTo(2, 4);
+    expect(dets[1].h).toBeCloseTo(2, 4);
+  });
+
+  it("drops everything when the threshold exceeds all scores", () => {
+    expect(decode(out, spec, pre, 0.95)).toHaveLength(0);
+  });
+});

frontend/editor/src/proprietary/components/shared/config/configSections/AdminFormDetectionSection.tsx

@@ -55,6 +55,7 @@ export default function AdminFormDetectionSection() {
   const enabled = status?.enabled ?? true;
   const executionMode: FormDetectionExecutionMode =
     status?.executionMode ?? "auto";
+  const serverEngineAvailable = status?.serverEngineAvailable ?? true;
 
   const catalog = status?.catalog ?? [];
   const selectData = useMemo(
@@ -196,9 +197,18 @@ export default function AdminFormDetectionSection() {
                   {
                     label: t("admin.formDetection.engine.server", "Server"),
                     value: "server",
+                    disabled: !serverEngineAvailable,
                   },
                 ]}
               />
+              {!serverEngineAvailable ? (
+                <Text size="xs" c="dimmed" mt={6}>
+                  {t(
+                    "admin.formDetection.engine.serverUnavailable",
+                    "The server engine is not bundled in this build, so detection runs in the browser. Use Auto or Browser.",
+                  )}
+                </Text>
+              ) : null}
             </div>
 
             {inFlight ? (