Make memory and context views mobile-friendly (#813)

* Changes from fix/memory-and-context-mobile-friendly

* fix: Improve file extension detection and add path traversal protection

* refactor: Extract file extension utilities and add path traversal guards

Code review improvements:
- Extract isMarkdownFilename and isImageFilename to shared image-utils.ts
- Remove duplicated code from context-view.tsx and memory-view.tsx
- Add path traversal guard for context fixture utilities (matching memory)
- Add 7 new tests for context fixture path traversal protection
- Total 61 tests pass

Addresses code review feedback from PR #813

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* test: Add e2e tests for profiles crud and board background persistence

* Update apps/ui/playwright.config.ts

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* fix: Add robust test navigation handling and file filtering

* fix: Format NODE_OPTIONS configuration on single line

* test: Update profiles and board background persistence tests

* test: Replace iPhone 13 Pro with Pixel 5 for mobile test consistency

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

apps/ui/tests/utils/core/interactions.ts

@@ -1,6 +1,5 @@
 import { Page, expect } from '@playwright/test';
 import { getByTestId, getButtonByText } from './elements';
-import { waitForSplashScreenToDisappear } from './waiting';
 
 /**
  * Get the platform-specific modifier key (Meta for Mac, Control for Windows/Linux)
@@ -23,10 +22,10 @@ export async function pressModifierEnter(page: Page): Promise<void> {
  * Waits for the element to be visible before clicking to avoid flaky tests
  */
 export async function clickElement(page: Page, testId: string): Promise<void> {
-  // Wait for splash screen to disappear first (safety net)
-  await waitForSplashScreenToDisappear(page, 5000);
+  // Splash screen waits are handled by navigation helpers (navigateToContext, navigateToMemory, etc.)
+  // before any clickElement calls, so we skip the splash check here to avoid blocking when
+  // other fixed overlays (e.g. HeaderActionsPanel backdrop at z-[60]) are present on the page.
   const element = page.locator(`[data-testid="${testId}"]`);
-  // Wait for element to be visible and stable before clicking
   await element.waitFor({ state: 'visible', timeout: 10000 });
   await element.click();
 }