feat: implement stability fixes and enhance error handling

src/lib/antigravity/stream-error-utils.ts

@@ -0,0 +1,75 @@
+/**
+ * Stream Error Utilities
+ * Classifies network errors and formats user-friendly messages
+ *
+ * Problem: Technical error messages confuse users
+ * Solution: Classify errors and provide localized, actionable messages
+ */
+
+export interface ClassifiedError {
+  type: string;
+  message: string;
+}
+
+/**
+ * Classify a stream error and return user-friendly message
+ *
+ * @param error - The error object
+ * @returns Classified error with type and localized message
+ */
+export function classifyStreamError(error: Error): ClassifiedError {
+  const msg = error.message.toLowerCase();
+
+  if (msg.includes('timeout') || msg.includes('timedout')) {
+    return {
+      type: 'timeout_error',
+      message: 'Request timed out. Please check your network connection or try again later.',
+    };
+  }
+
+  if (msg.includes('econnrefused') || msg.includes('connect')) {
+    return {
+      type: 'connection_error',
+      message: 'Unable to connect to server. Please check your network.',
+    };
+  }
+
+  if (msg.includes('enotfound') || msg.includes('network') || msg.includes('dns')) {
+    return {
+      type: 'network_error',
+      message: 'Network connection failed. Please check your network settings.',
+    };
+  }
+
+  if (msg.includes('socket') || msg.includes('aborted') || msg.includes('reset')) {
+    return {
+      type: 'stream_error',
+      message: 'Data transfer interrupted. Please try again later.',
+    };
+  }
+
+  return {
+    type: 'unknown_error',
+    message: `Unknown error occurred: ${error.message.substring(0, 100)}`,
+  };
+}
+
+/**
+ * Format error as SSE event for Claude protocol
+ *
+ * @param errorType - Error type string
+ * @param message - User-friendly message
+ * @returns SSE-formatted error event string
+ */
+export function formatErrorForSSE(errorType: string, message: string): string {
+  const errorEvent = {
+    type: 'error',
+    error: {
+      type: errorType,
+      message: message,
+      code: 'stream_error',
+    },
+  };
+
+  return `event: error\ndata: ${JSON.stringify(errorEvent)}\n\n`;
+}