fix: fall back to default certs when CA bundle path doesn't exist (#7352)

_resolve_verify() returned stale CA bundle paths from auth.json without
checking if the file exists. When a user logs into Nous Portal on their
host (where SSL_CERT_FILE points to a valid cert), that path gets
persisted in auth.json. Running hermes model later in Docker where the
host path doesn't exist caused FileNotFoundError bubbling up as
'Could not verify credentials: [Errno 2] No such file or directory'.

Now _resolve_verify validates the path exists before returning it. If
missing, logs a warning and falls back to True (default certifi-based
TLS verification).

tests/hermes_cli/test_auth_nous_provider.py

@@ -1,6 +1,7 @@
 """Regression tests for Nous OAuth refresh + agent-key mint interactions."""
 
 import json
+import os
 from datetime import datetime, timezone
 from pathlib import Path
 
@@ -10,6 +11,80 @@ import pytest
 from hermes_cli.auth import AuthError, get_provider_auth_state, resolve_nous_runtime_credentials
 
 
+# =============================================================================
+# _resolve_verify: CA bundle path validation
+# =============================================================================
+
+
+class TestResolveVerifyFallback:
+    """Verify _resolve_verify falls back to True when CA bundle path doesn't exist."""
+
+    def test_missing_ca_bundle_in_auth_state_falls_back(self):
+        from hermes_cli.auth import _resolve_verify
+
+        result = _resolve_verify(auth_state={
+            "tls": {"insecure": False, "ca_bundle": "/nonexistent/ca-bundle.pem"},
+        })
+        assert result is True
+
+    def test_valid_ca_bundle_in_auth_state_is_returned(self, tmp_path):
+        from hermes_cli.auth import _resolve_verify
+
+        ca_file = tmp_path / "ca-bundle.pem"
+        ca_file.write_text("fake cert")
+        result = _resolve_verify(auth_state={
+            "tls": {"insecure": False, "ca_bundle": str(ca_file)},
+        })
+        assert result == str(ca_file)
+
+    def test_missing_ssl_cert_file_env_falls_back(self, monkeypatch):
+        from hermes_cli.auth import _resolve_verify
+
+        monkeypatch.setenv("SSL_CERT_FILE", "/nonexistent/ssl-cert.pem")
+        monkeypatch.delenv("HERMES_CA_BUNDLE", raising=False)
+        result = _resolve_verify(auth_state={"tls": {}})
+        assert result is True
+
+    def test_missing_hermes_ca_bundle_env_falls_back(self, monkeypatch):
+        from hermes_cli.auth import _resolve_verify
+
+        monkeypatch.setenv("HERMES_CA_BUNDLE", "/nonexistent/hermes-ca.pem")
+        monkeypatch.delenv("SSL_CERT_FILE", raising=False)
+        result = _resolve_verify(auth_state={"tls": {}})
+        assert result is True
+
+    def test_insecure_takes_precedence_over_missing_ca(self):
+        from hermes_cli.auth import _resolve_verify
+
+        result = _resolve_verify(
+            insecure=True,
+            auth_state={"tls": {"ca_bundle": "/nonexistent/ca.pem"}},
+        )
+        assert result is False
+
+    def test_no_ca_bundle_returns_true(self, monkeypatch):
+        from hermes_cli.auth import _resolve_verify
+
+        monkeypatch.delenv("HERMES_CA_BUNDLE", raising=False)
+        monkeypatch.delenv("SSL_CERT_FILE", raising=False)
+        result = _resolve_verify(auth_state={"tls": {}})
+        assert result is True
+
+    def test_explicit_ca_bundle_param_missing_falls_back(self):
+        from hermes_cli.auth import _resolve_verify
+
+        result = _resolve_verify(ca_bundle="/nonexistent/explicit-ca.pem")
+        assert result is True
+
+    def test_explicit_ca_bundle_param_valid_is_returned(self, tmp_path):
+        from hermes_cli.auth import _resolve_verify
+
+        ca_file = tmp_path / "explicit-ca.pem"
+        ca_file.write_text("fake cert")
+        result = _resolve_verify(ca_bundle=str(ca_file))
+        assert result == str(ca_file)
+
+
 def _setup_nous_auth(
     hermes_home: Path,
     *,