Test/add e2e and unit testing (#1282)

* feat: add string utility tests and vitest browser configuration

* feat: add Playwright for end-to-end testing and update snapshots

- Introduced Playwright for E2E testing with a new configuration file.
- Added test scripts to package.json for running E2E tests.
- Updated package-lock.json and package.json with new dependencies for Playwright and types.
- Created new SVG snapshot files for various layers (ruler, scaleBar, temperature, terrain, vignette, zones) to support visual testing.
- Excluded e2e directory from TypeScript compilation.

* Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Add SVG layer snapshots for various components

- Added ruler layer snapshot with hidden display.
- Added scale bar layer snapshot with detailed structure and styling.
- Added temperature layer snapshot with opacity and stroke settings.
- Added terrain layer snapshot with ocean and land heights groups.
- Added vignette layer snapshot with mask and opacity settings.
- Added zones layer snapshot with specified opacity and stroke settings.

* fix: update Playwright browser installation command to use npx

* Update snapshots

* refactor: remove unused layer tests and their corresponding snapshots as fonts are unpredictable

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

package.json

@@ -16,14 +16,23 @@
   "scripts": {
     "dev": "vite",
     "build": "tsc && vite build",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest",
+    "test:browser": "vitest --config=vitest.browser.config.ts",
+    "test:e2e": "playwright test"
   },
   "devDependencies": {
+    "@playwright/test": "^1.57.0",
     "@types/d3": "^7.4.3",
     "@types/delaunator": "^5.0.3",
+    "@types/node": "^25.0.10",
     "@types/polylabel": "^1.1.3",
+    "@vitest/browser": "^4.0.18",
+    "@vitest/browser-playwright": "^4.0.18",
+    "playwright": "^1.57.0",
     "typescript": "^5.9.3",
-    "vite": "^7.3.1"
+    "vite": "^7.3.1",
+    "vitest": "^4.0.18"
   },
   "dependencies": {
     "alea": "^1.0.1",