fix: preserve default undecoded result

Author: Copilot

lib/MessageDecoder.test.ts

@@ -61,4 +61,30 @@ describe('MessageDecoder', () => {
     expect(decodeResult.message.label).toBe('H1');
     expect(decodeResult.formatted.items.length).toBe(5);
   });
+
+  test('preserves default fallback result when no plugin decodes', () => {
+    const message = {
+      label: '44',
+      text: 'GARBAGE TEXT THAT SHOULD NOT MATCH',
+    };
+
+    const decodeResult = decoder.decode(message);
+
+    expect(decodeResult.decoded).toBe(false);
+    expect(decodeResult.error).toBe('No known decoder plugin for this message');
+    expect(decodeResult.decoder).toEqual({
+      name: 'none',
+      type: 'none',
+      decodeLevel: 'none',
+    });
+    expect(decodeResult.message).toBe(message);
+    expect(decodeResult.remaining).toEqual({
+      text: message.text,
+    });
+    expect(decodeResult.raw).toEqual({});
+    expect(decodeResult.formatted).toEqual({
+      description: 'Not Decoded',
+      items: [],
+    });
+  });
 });

lib/MessageDecoder.ts

@@ -168,8 +168,9 @@ export class MessageDecoder {
 
     for (let i = 0; i < usablePlugins.length; i++) {
       const plugin = usablePlugins[i];
-      result = plugin.decode(message, options);
-      if (result.decoded) {
+      const pluginResult = plugin.decode(message, options);
+      if (pluginResult.decoded) {
+        result = pluginResult;
         break;
       }
     }