feat(gemini): extend x-goog-api-client to TTS path + cite Google requirement

Follow-up to salvaged PR #47385. Google's partner-integration guidance
requires platform/library clients to send the x-goog-api-client header
(company-product/version) on Gemini API calls:
https://ai.google.dev/gemini-api/docs/partner-integration

- tools/tts_tool.py: add the header to the native Gemini TTS generateContent
  call (sibling site the original PR missed)
- agent/gemini_native_adapter.py: cite the requirement doc inline
- tests/tools/test_tts_gemini.py: assert the TTS header is present
- scripts/release.py: AUTHOR_MAP entry for dharmadhikari@google.com

agent/gemini_native_adapter.py

@@ -889,6 +889,9 @@ class GeminiNativeClient:
             "Content-Type": "application/json",
             "Accept": "application/json",
             "x-goog-api-key": self.api_key,
+            # Google requires platform/library clients to identify themselves
+            # via x-goog-api-client (company-product/version format).
+            # See https://ai.google.dev/gemini-api/docs/partner-integration
             "User-Agent": f"hermes-agent/{_HERMES_VERSION} (gemini-native)",
             "X-Goog-Api-Client": f"hermes-agent/{_HERMES_VERSION}",
         }

scripts/release.py

@@ -475,6 +475,7 @@ AUTHOR_MAP = {
     "bzarnitz13@gmail.com": "Beandon13",
     "tony@tonysimons.dev": "asimons81",
     "jetha@google.com": "jethac",
+    "dharmadhikari@google.com": "vishal-dharm",
     "jani@0xhoneyjar.xyz": "deep-name",
     # LINE messaging plugin (synthesis PR)
     "32443648+leepoweii@users.noreply.github.com": "leepoweii",

tests/tools/test_tts_gemini.py

@@ -115,6 +115,19 @@ class TestGenerateGeminiTts:
         # Audio payload should match the PCM we put in
         assert data[44:] == fake_pcm_bytes
 
+    def test_x_goog_api_client_header_is_set(self, tmp_path, monkeypatch, mock_gemini_response):
+        """Google requires platform clients to send x-goog-api-client."""
+        from tools.tts_tool import _generate_gemini_tts
+
+        monkeypatch.setenv("GEMINI_API_KEY", "test-key")
+
+        with patch("requests.post", return_value=mock_gemini_response) as mock_post:
+            _generate_gemini_tts("Hi", str(tmp_path / "test.wav"), {})
+
+        headers = mock_post.call_args[1]["headers"]
+        assert "X-Goog-Api-Client" in headers
+        assert headers["X-Goog-Api-Client"].startswith("hermes-agent/")
+
     def test_default_voice_and_model(self, tmp_path, monkeypatch, mock_gemini_response):
         from tools.tts_tool import (
             DEFAULT_GEMINI_TTS_MODEL,

tools/tts_tool.py

@@ -1617,11 +1617,21 @@ def _generate_gemini_tts(text: str, output_path: str, tts_config: Dict[str, Any]
         },
     }
 
+    try:
+        from hermes_cli import __version__ as _hermes_version
+    except Exception:
+        _hermes_version = "0.0.0"
+
     endpoint = f"{base_url}/models/{model}:generateContent"
     response = requests.post(
         endpoint,
         params={"key": api_key},
-        headers={"Content-Type": "application/json"},
+        headers={
+            "Content-Type": "application/json",
+            # Google requires platform/library clients to identify themselves
+            # via x-goog-api-client. See https://ai.google.dev/gemini-api/docs/partner-integration
+            "X-Goog-Api-Client": f"hermes-agent/{_hermes_version}",
+        },
         json=payload,
         timeout=60,
     )