feat: #58 Tests E2E Playwright — 44 tests desktop + CI

- playwright.config.ts: chromium-desktop + chromium-mobile
- tests/e2e/obsigate.spec.ts: 44 tests en 11 sections
  - Dashboard & Navigation (8 tests)
  - Full-Text Search (10 tests)
  - File Navigation & Viewer (5 tests)
  - Editor (4 tests: Forge, basic modal, Ctrl+S)
  - Mermaid Diagrams (2 tests)
  - PDF Export, Dark Mode, Responsive, Saved Searches
  - Keyboard Shortcuts (Ctrl+K, /, Escape)
  - Context Menu directory
- CI: nouveau job e2e dans .gitea/workflows/ci.yml
- ROADMAP: #58 marque FAIT
- .gitignore: node_modules, test-results, playwright-report

.gitignore

@@ -16,3 +16,6 @@ data/
 .coverage
 .coverage
 odysseus/
+node_modules/
+test-results/
+playwright-report/