refactor(example): migrate to Vite dev server and update Extism dependency

Makefile

@@ -30,8 +30,8 @@ test-plugin:
 	@extism call $(BUILD_DIR)/$(BINARY) generate --input '{"credential":"dGVzdA=="}' --wasi
 
 serve: build
-	@echo "Open http://localhost:8080/example/ in your browser"
-	@python3 -m http.server 8080 -d example
+	@echo "Starting Vite dev server at http://localhost:8080"
+	@cd example && npm run dev
 
 lint:
 	@golangci-lint run ./...
@@ -54,6 +54,7 @@ deps:
 	@go install github.com/sqlc-dev/sqlc/cmd/sqlc@latest
 	@go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
 	@go install mvdan.cc/gofumpt@latest
+	@cd example && npm install
 	@echo "Install Extism CLI: https://extism.org/docs/install"
 
 verify: fmt vet lint test