fix(openrouter): use canonical X-Title attribution header

OpenRouter's dashboard attributes usage via the `X-Title` header.
Hermes was sending `X-OpenRouter-Title`, which OpenRouter does not
recognize, so Hermes usage showed up unlabeled. Rename to `X-Title`
to match the canonical header (already used elsewhere in the same
file via _AI_GATEWAY_HEADERS).

Salvages the core fix from @JTroyerOvermatch's PR #13649. Dropped the
PR's `HERMES_OPENROUTER_TITLE` / `HERMES_OPENROUTER_REFERER` env-var
override plumbing per the '.env is for secrets only' policy — if
per-deployment attribution is needed later it should go under
`openrouter.title` / `openrouter.referer` in config.yaml instead.

agent/auxiliary_client.py

@@ -259,10 +259,12 @@ _PROVIDERS_WITHOUT_VISION: frozenset = frozenset({
     "kimi-coding-cn",
 })
 
-# OpenRouter app attribution headers (base — always sent)
+# OpenRouter app attribution headers (base — always sent).
+# `X-Title` is the canonical attribution header OpenRouter's dashboard
+# reads; the previous `X-OpenRouter-Title` label was not recognized there.
 _OR_HEADERS_BASE = {
     "HTTP-Referer": "https://hermes-agent.nousresearch.com",
-    "X-OpenRouter-Title": "Hermes Agent",
+    "X-Title": "Hermes Agent",
     "X-OpenRouter-Categories": "productivity,cli-agent",
 }
 

tests/agent/test_openrouter_response_cache.py

@@ -19,7 +19,7 @@ class TestBuildOrHeaders:
 
         headers = build_or_headers(or_config={"response_cache": False})
         assert headers["HTTP-Referer"] == "https://hermes-agent.nousresearch.com"
-        assert headers["X-OpenRouter-Title"] == "Hermes Agent"
+        assert headers["X-Title"] == "Hermes Agent"
         assert headers["X-OpenRouter-Categories"] == "productivity,cli-agent"
 
     def test_cache_enabled(self):

tests/run_agent/test_provider_attribution_headers.py

@@ -24,7 +24,7 @@ def test_openrouter_base_url_applies_or_headers(mock_openai):
 
     headers = agent._client_kwargs["default_headers"]
     assert headers["HTTP-Referer"] == "https://hermes-agent.nousresearch.com"
-    assert headers["X-OpenRouter-Title"] == "Hermes Agent"
+    assert headers["X-Title"] == "Hermes Agent"
 
 
 @patch("run_agent.OpenAI")