Add network map UX and theme support.

Introduce network map view/components with filtering and positioning, expand contacts/map backend fields and migrations, and add a persistent light/dark theme toggle with graph label color updates for readability.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/vitest.config.js

@@ -0,0 +1,11 @@
+import { defineConfig } from 'vitest/config'
+import vue from '@vitejs/plugin-vue'
+
+export default defineConfig({
+  plugins: [vue()],
+  test: {
+    environment: 'jsdom',
+    globals: true,
+    include: ['src/**/*.test.js'],
+  },
+})