Fix CI test failures by building dashboard before tests

- Add dashboard build step to test target
- Ensures web/dist/* files exist for go:embed directives
- Prevents "pattern web/dist/*: no matching files found" errors

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: dan-v

Makefile

@@ -57,6 +57,8 @@ build-all: ## Build for multiple platforms using Docker
 
 test: ## Run all tests
 	@echo "Running all tests..."
+	@echo "Building dashboard for embedded tests..."
+	@./scripts/build-dashboard.sh
 	@echo "Building Lambda function for embedded tests..."
 	@mkdir -p $(BUILD_DIR)
 	@mkdir -p cmd/lambda-nat-proxy/assets