Preserve error context in JSON parsing error handlers

Add { cause: e } to error constructors in getResponseJson to preserve
original error context for debugging. This follows the "no silent
failures" principle by maintaining the full error chain when wrapping
SyntaxError and unknown JSON parsing errors.

Author: jdalton

src/http-client.ts

@@ -205,6 +205,7 @@ export async function getResponseJson(
       // Attach the original response text for better error reporting.
       const enhancedError = new Error(
         `Socket API - Invalid JSON response:\n${responseBody}\n→ ${e.message}`,
+        { cause: e },
       ) as SyntaxError & {
         originalResponse?: string
       }
@@ -218,9 +219,9 @@ export async function getResponseJson(
       throw e
     }
     // Handle non-Error objects thrown by JSON parsing.
-    const unknownError = new Error(
-      'Unknown JSON parsing error',
-    ) as SyntaxError & {
+    const unknownError = new Error('Unknown JSON parsing error', {
+      cause: e,
+    }) as SyntaxError & {
       originalResponse?: string
     }
     unknownError.name = 'SyntaxError'