feat: add Google code retrieval across desktop CLI and MCP

apps/desktop/tests/match-display.test.mjs

@@ -80,3 +80,8 @@ test('optional reasons use real source routes and never claim semantic word conf
   assert.equal(matchExplanation({match_kind:'hybrid',source:{kind:'page',number:2}}).semanticPassage,false);
   assert.doesNotMatch(JSON.stringify(text),/confidence|percent|importance/);
 });
+
+test('code passage reasons retain actual indexed source line', () => {
+  assert.match(matchExplanation({match_kind:'semantic', source:{kind:'line',number:97}}).reason, /at line 97/);
+  assert.match(matchExplanation({match_kind:'hybrid', source:{kind:'line',number:97}}).reason, /showing the passage at line 97/);
+});