feat: integrate GitHub Copilot providers across Hermes

Add first-class GitHub Copilot and Copilot ACP provider support across
model selection, runtime provider resolution, CLI sessions, delegated
subagents, cron jobs, and the Telegram gateway.

This also normalizes Copilot model catalogs and API modes, introduces a
Copilot ACP OpenAI-compatible shim, and fixes service-mode auth by
resolving Homebrew-installed gh binaries under launchd.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/agent/test_auxiliary_client.py

@@ -248,6 +248,31 @@ class TestVisionClientFallback:
         assert client.__class__.__name__ == "AnthropicAuxiliaryClient"
         assert model == "claude-haiku-4-5-20251001"
 
+    def test_resolve_provider_client_copilot_uses_runtime_credentials(self, monkeypatch):
+        monkeypatch.delenv("GITHUB_TOKEN", raising=False)
+        monkeypatch.delenv("GH_TOKEN", raising=False)
+
+        with (
+            patch(
+                "hermes_cli.auth.resolve_api_key_provider_credentials",
+                return_value={
+                    "provider": "copilot",
+                    "api_key": "gh-cli-token",
+                    "base_url": "https://api.githubcopilot.com",
+                    "source": "gh auth token",
+                },
+            ),
+            patch("agent.auxiliary_client.OpenAI") as mock_openai,
+        ):
+            client, model = resolve_provider_client("copilot", model="gpt-5.4")
+
+        assert client is not None
+        assert model == "gpt-5.4"
+        call_kwargs = mock_openai.call_args.kwargs
+        assert call_kwargs["api_key"] == "gh-cli-token"
+        assert call_kwargs["base_url"] == "https://api.githubcopilot.com"
+        assert call_kwargs["default_headers"]["Editor-Version"]
+
     def test_vision_auto_uses_anthropic_when_no_higher_priority_backend(self, monkeypatch):
         monkeypatch.setenv("ANTHROPIC_API_KEY", "sk-ant-api03-key")
         with (