refactor(config): document resolve.conditions safety for SSR builds

Verified: SvelteKit's plugin overrides resolve.conditions for SSR
builds. The global 'browser' condition only affects vitest and dev.
Build output confirmed correct with npm run build.

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

frontend/vite.config.ts

@@ -10,6 +10,8 @@ export default defineConfig({
 		environment: 'jsdom',
 		setupFiles: ['src/test-setup.ts']
 	},
+	// Required for vitest: resolves Svelte to client entry (not server).
+	// SvelteKit's plugin overrides this for SSR builds — verified safe.
 	resolve: {
 		conditions: ['browser']
 	}