test(ui): update locators in tests to use role-based queries

- Refactored locators in BasePage, HomePage, SignInPage, and SignUpPage to utilize role-based queries for improved accessibility and consistency across the UI tests.

ui/tests/base-page.ts

@@ -18,7 +18,7 @@ export abstract class BasePage {
     // Common locators that most pages share
     this.title = page.locator("h1, h2, [role='heading']").first();
     this.loadingIndicator = page.getByRole("status", { name: "Loading" });
-    this.themeToggle = page.getByLabel("Toggle theme");
+    this.themeToggle = page.getByRole("button", { name: "Toggle theme" });
   }
 
   // Common navigation methods

ui/tests/home/home-page.ts

@@ -25,7 +25,7 @@ export class HomePage extends BasePage {
     
     // Main content elements
     this.mainContent = page.locator("main");
-    this.breadcrumbs = page.getByLabel("Breadcrumbs");
+    this.breadcrumbs = page.getByRole("navigation", { name: "Breadcrumbs" });
     this.overviewHeading = page.getByRole("heading", { name: "Overview", exact: true });
     
     // Navigation elements

ui/tests/sign-in/sign-in-page.ts

@@ -45,8 +45,8 @@ export class SignInPage extends BasePage {
     this.homePage = new HomePage(page);
     
     // Form elements
-    this.emailInput = page.getByLabel("Email");
-    this.passwordInput = page.getByLabel("Password");
+    this.emailInput = page.getByRole("textbox", { name: "Email" });
+    this.passwordInput = page.getByRole("textbox", { name: "Password" });
     this.loginButton = page.getByRole("button", { name: "Log in" });
     this.form = page.locator("form");
     
@@ -67,7 +67,7 @@ export class SignInPage extends BasePage {
     
     // SAML specific elements
     this.samlModeTitle = page.getByRole("heading", { name: "Sign in with SAML SSO" });
-    this.samlEmailInput = page.getByLabel("Email");
+    this.samlEmailInput = page.getByRole("textbox", { name: "Email" });
   }
 
   // Navigation methods

ui/tests/sign-up/sign-up-page.ts

@@ -32,7 +32,7 @@ export class SignUpPage extends BasePage {
     // Prefer stable name attributes to avoid label ambiguity in composed inputs
     this.nameInput = page.locator('input[name="name"]');
     this.companyInput = page.locator('input[name="company"]');
-    this.emailInput = page.getByLabel("Email");
+    this.emailInput = page.getByRole("textbox", { name: "Email" });
     this.passwordInput = page.locator('input[name="password"]');
     this.confirmPasswordInput = page.locator('input[name="confirmPassword"]');
     this.invitationTokenInput = page.locator('input[name="invitationToken"]');