refactor(cli): Finalize OpenAI Codex Integration with OAuth

- Enhanced Codex model discovery by fetching available models from the API, with fallback to local cache and defaults.
- Updated the context compressor's summary target tokens to 2500 for improved performance.
- Added external credential detection for Codex CLI to streamline authentication.
- Refactored various components to ensure consistent handling of authentication and model selection across the application.

tests/test_cli_init.py

@@ -0,0 +1,80 @@
+"""Tests for HermesCLI initialization -- catches configuration bugs
+that only manifest at runtime (not in mocked unit tests)."""
+
+import os
+import sys
+from unittest.mock import patch, MagicMock
+
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+
+def _make_cli(**kwargs):
+    """Create a HermesCLI instance with minimal mocking."""
+    from cli import HermesCLI
+    with patch("cli.get_tool_definitions", return_value=[]):
+        return HermesCLI(**kwargs)
+
+
+class TestMaxTurnsResolution:
+    """max_turns must always resolve to a positive integer, never None."""
+
+    def test_default_max_turns_is_integer(self):
+        cli = _make_cli()
+        assert isinstance(cli.max_turns, int)
+        assert cli.max_turns > 0
+
+    def test_explicit_max_turns_honored(self):
+        cli = _make_cli(max_turns=25)
+        assert cli.max_turns == 25
+
+    def test_none_max_turns_gets_default(self):
+        cli = _make_cli(max_turns=None)
+        assert isinstance(cli.max_turns, int)
+        assert cli.max_turns > 0
+
+    def test_env_var_max_turns(self, monkeypatch):
+        """Env var is used when config file doesn't set max_turns."""
+        monkeypatch.setenv("HERMES_MAX_ITERATIONS", "42")
+        import cli as cli_module
+        original = cli_module.CLI_CONFIG["agent"].get("max_turns")
+        cli_module.CLI_CONFIG["agent"]["max_turns"] = None
+        try:
+            cli_obj = _make_cli()
+            assert cli_obj.max_turns == 42
+        finally:
+            if original is not None:
+                cli_module.CLI_CONFIG["agent"]["max_turns"] = original
+
+    def test_max_turns_never_none_for_agent(self):
+        """The value passed to AIAgent must never be None (causes TypeError in run_conversation)."""
+        cli = _make_cli()
+        assert cli.max_turns is not None
+
+
+class TestVerboseAndToolProgress:
+    def test_default_verbose_is_bool(self):
+        cli = _make_cli()
+        assert isinstance(cli.verbose, bool)
+
+    def test_tool_progress_mode_is_string(self):
+        cli = _make_cli()
+        assert isinstance(cli.tool_progress_mode, str)
+        assert cli.tool_progress_mode in ("off", "new", "all", "verbose")
+
+
+class TestProviderResolution:
+    def test_api_key_is_string_or_none(self):
+        cli = _make_cli()
+        assert cli.api_key is None or isinstance(cli.api_key, str)
+
+    def test_base_url_is_string(self):
+        cli = _make_cli()
+        assert isinstance(cli.base_url, str)
+        assert cli.base_url.startswith("http")
+
+    def test_model_is_string(self):
+        cli = _make_cli()
+        assert isinstance(cli.model, str)
+        assert len(cli.model) > 0