fix(viewer): remove unrelated branding on current main

src/main/java/com/clearfolio/viewer/controller/ViewerUiController.java

@@ -129,7 +129,7 @@ private static String viewerShellHtml(String docId, String initialState) {
 
                     <footer class="app-footer" role="contentinfo">
                       <div class="app-footer__inner">
-                        <small>Copyright (c) 2026 by HYOSUNG. All rights reserved.</small>
+                        <small>Clearfolio Viewer · Apache-2.0</small>
                       </div>
                     </footer>
 
@@ -317,7 +317,7 @@ private static String demoShellHtml() {
 
                     <footer class="app-footer" role="contentinfo">
                       <div class="app-footer__inner">
-                        <small>Copyright (c) 2026 by HYOSUNG. All rights reserved.</small>
+                        <small>Clearfolio Viewer · Apache-2.0</small>
                       </div>
                     </footer>
 

src/test/java/com/clearfolio/viewer/controller/ViewerUiBrandingContractTest.java

@@ -0,0 +1,57 @@
+package com.clearfolio.viewer.controller;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.UUID;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+/**
+ * Regression tests that keep the distributable Clearfolio UI free of unrelated company branding.
+ */
+class ViewerUiBrandingContractTest {
+
+    private WebTestClient webTestClient;
+
+    /**
+     * Creates a controller-only client for deterministic HTML contract checks.
+     */
+    @BeforeEach
+    void setUp() {
+        webTestClient = WebTestClient.bindToController(new ViewerUiController()).build();
+    }
+
+    /**
+     * Requires the root shell to identify the product without claiming HYOSUNG ownership.
+     */
+    @Test
+    void rootShellDoesNotClaimHyosungOwnership() {
+        webTestClient.get()
+                .uri("/")
+                .exchange()
+                .expectStatus().isOk()
+                .expectBody(String.class)
+                .value(body -> {
+                    assertThat(body).contains("Clearfolio Viewer");
+                    assertThat(body).doesNotContain("HYOSUNG");
+                });
+    }
+
+    /**
+     * Requires document viewer shells to use the same product-owned branding contract.
+     */
+    @Test
+    void documentViewerDoesNotClaimHyosungOwnership() {
+        webTestClient.get()
+                .uri("/viewer/{docId}", UUID.randomUUID())
+                .exchange()
+                .expectStatus().isOk()
+                .expectBody(String.class)
+                .value(body -> {
+                    assertThat(body).contains("Clearfolio Viewer");
+                    assertThat(body).doesNotContain("HYOSUNG");
+                });
+    }
+}