feat(tutorial): enhance help button visibility and add dialog tests

- Introduced a mechanism to hide the help button when modal dialogs are open by adding `helpButtonHidden` state in the tutorial controller.
- Updated various components to set the help button visibility based on dialog states.
- Added tests to verify help button visibility during reward and task confirmation dialogs.
- Created new E2E tests for dialog help button functionality across different assignment views.
- Refactored existing dialog components to utilize the new help button visibility logic.
- Added unit tests for `RewardConfirmDialog` and `TaskConfirmDialog` to ensure correct titles are rendered based on task type.
- Enhanced `HelpButton` component tests to validate visibility based on tutorial state.

frontend/playwright.config.ts

@@ -184,6 +184,16 @@ export default defineConfig({
       use: { ...devices['Desktop Chrome'], storageState: STORAGE_STATE_TUTORIAL },
       dependencies: ['setup-tutorial'],
       testMatch: [/mode_parent\/tutorial\/.+\.spec\.ts/],
+      testIgnore: [/mode_parent\/tutorial\/dialog-help-button\.spec\.ts/],
+    },
+
+    {
+      // Bucket: dialog help-button/title tests — depends on the tutorial bucket
+      // so it reuses the isolated tutorial user without running concurrently.
+      name: 'chromium-dialog',
+      use: { ...devices['Desktop Chrome'], storageState: STORAGE_STATE_TUTORIAL },
+      dependencies: ['chromium-tutorial'],
+      testMatch: [/mode_parent\/tutorial\/dialog-help-button\.spec\.ts/],
     },
 
     {