fix: use JSONParseWithException for proper error handling

- SQLClient.cpp: Fix bug where RETURN_IF_EXCEPTION after JSONParse would
  never trigger on JSON parse failure since JSONParse doesn't throw
- BunString.cpp: Simplify by using JSONParseWithException instead of
  manually checking for empty result and throwing

JSONParse returns an empty JSValue on failure without throwing, so
RETURN_IF_EXCEPTION will not catch parsing errors. JSONParseWithException
properly throws a SyntaxError which RETURN_IF_EXCEPTION can catch.

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

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

Author: Claude Bot

src/bun.js/bindings/BunString.cpp

@@ -473,12 +473,7 @@ extern "C" [[ZIG_EXPORT(zero_is_throw)]] JSC::EncodedJSValue BunString__toJSON(
     BunString* bunString)
 {
     auto scope = DECLARE_THROW_SCOPE(globalObject->vm());
-    JSC::JSValue result = JSC::JSONParse(globalObject, bunString->toWTFString());
-
-    if (!result && !scope.exception()) {
-        scope.throwException(globalObject, createSyntaxError(globalObject, "Failed to parse JSON"_s));
-    }
-
+    JSC::JSValue result = JSC::JSONParseWithException(globalObject, bunString->toWTFString());
     RETURN_IF_EXCEPTION(scope, {});
 
     return JSC::JSValue::encode(result);

src/bun.js/bindings/SQLClient.cpp

@@ -188,7 +188,7 @@ static JSC::JSValue toJS(JSC::VM& vm, JSC::JSGlobalObject* globalObject, DataCel
     case DataCellTag::Json: {
         if (cell.value.json) {
             auto str = WTF::String(cell.value.json);
-            JSC::JSValue json = JSC::JSONParse(globalObject, str);
+            JSC::JSValue json = JSC::JSONParseWithException(globalObject, str);
             RETURN_IF_EXCEPTION(scope, {});
             return json;
         }