fix(auth): honor SSL CA env vars across httpx + requests callsites

- hermes_cli/auth.py: add _default_verify() with macOS Homebrew certifi
  fallback (mirrors weixin 3a0ec1d93). Extend env var chain to include
  REQUESTS_CA_BUNDLE so one env var works across httpx + requests paths.
- agent/model_metadata.py: add _resolve_requests_verify() reading
  HERMES_CA_BUNDLE / REQUESTS_CA_BUNDLE / SSL_CERT_FILE in priority
  order. Apply explicit verify= to all 6 requests.get callsites.
- Tests: 18 new unit tests + autouse platform pin on existing
  TestResolveVerifyFallback to keep its "returns True" assertions
  platform-independent.

Empirically verified against self-signed HTTPS server: requests honors
REQUESTS_CA_BUNDLE only; httpx honors SSL_CERT_FILE only. Hermes now
honors all three everywhere.

Triggered by Discord reports — Nous OAuth SSL failure on macOS
Homebrew Python; custom provider self-signed cert ignored despite
REQUESTS_CA_BUNDLE set in env.

tests/agent/test_model_metadata_ssl.py

@@ -0,0 +1,90 @@
+"""Tests for _resolve_requests_verify() env var precedence.
+
+Verifies that custom provider `/models` fetches honour the three supported
+CA bundle env vars (HERMES_CA_BUNDLE, REQUESTS_CA_BUNDLE, SSL_CERT_FILE)
+in the documented priority order, and that non-existent paths are
+skipped gracefully rather than breaking the request.
+
+No filesystem or network I/O required — we use tmp_path to create real
+CA bundle stand-in files and monkeypatch env vars.
+"""
+
+import os
+import sys
+from pathlib import Path
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+import pytest
+
+from agent.model_metadata import _resolve_requests_verify
+
+
+_CA_ENV_VARS = ("HERMES_CA_BUNDLE", "REQUESTS_CA_BUNDLE", "SSL_CERT_FILE")
+
+
+@pytest.fixture
+def clean_env(monkeypatch):
+    """Clear all three SSL env vars so each test starts from a known state."""
+    for var in _CA_ENV_VARS:
+        monkeypatch.delenv(var, raising=False)
+    return monkeypatch
+
+
+@pytest.fixture
+def bundle_file(tmp_path: Path) -> str:
+    """Create a placeholder CA bundle file and return its absolute path."""
+    path = tmp_path / "ca.pem"
+    path.write_text("-----BEGIN CERTIFICATE-----\nstub\n-----END CERTIFICATE-----\n")
+    return str(path)
+
+
+class TestResolveRequestsVerify:
+    def test_no_env_returns_true(self, clean_env):
+        assert _resolve_requests_verify() is True
+
+    def test_hermes_ca_bundle_returns_path(self, clean_env, bundle_file):
+        clean_env.setenv("HERMES_CA_BUNDLE", bundle_file)
+        assert _resolve_requests_verify() == bundle_file
+
+    def test_requests_ca_bundle_returns_path(self, clean_env, bundle_file):
+        clean_env.setenv("REQUESTS_CA_BUNDLE", bundle_file)
+        assert _resolve_requests_verify() == bundle_file
+
+    def test_ssl_cert_file_returns_path(self, clean_env, bundle_file):
+        clean_env.setenv("SSL_CERT_FILE", bundle_file)
+        assert _resolve_requests_verify() == bundle_file
+
+    def test_priority_hermes_over_requests(self, clean_env, tmp_path, bundle_file):
+        other = tmp_path / "other.pem"
+        other.write_text("stub")
+        clean_env.setenv("HERMES_CA_BUNDLE", bundle_file)
+        clean_env.setenv("REQUESTS_CA_BUNDLE", str(other))
+        assert _resolve_requests_verify() == bundle_file
+
+    def test_priority_requests_over_ssl_cert_file(self, clean_env, tmp_path, bundle_file):
+        other = tmp_path / "other.pem"
+        other.write_text("stub")
+        clean_env.setenv("REQUESTS_CA_BUNDLE", bundle_file)
+        clean_env.setenv("SSL_CERT_FILE", str(other))
+        assert _resolve_requests_verify() == bundle_file
+
+    def test_nonexistent_path_falls_through(self, clean_env, tmp_path, bundle_file):
+        missing = tmp_path / "does_not_exist.pem"
+        clean_env.setenv("HERMES_CA_BUNDLE", str(missing))
+        clean_env.setenv("REQUESTS_CA_BUNDLE", bundle_file)
+        assert _resolve_requests_verify() == bundle_file
+
+    def test_all_nonexistent_returns_true(self, clean_env, tmp_path):
+        missing1 = tmp_path / "a.pem"
+        missing2 = tmp_path / "b.pem"
+        missing3 = tmp_path / "c.pem"
+        clean_env.setenv("HERMES_CA_BUNDLE", str(missing1))
+        clean_env.setenv("REQUESTS_CA_BUNDLE", str(missing2))
+        clean_env.setenv("SSL_CERT_FILE", str(missing3))
+        assert _resolve_requests_verify() is True
+
+    def test_empty_string_env_var_ignored(self, clean_env, bundle_file):
+        clean_env.setenv("HERMES_CA_BUNDLE", "")
+        clean_env.setenv("REQUESTS_CA_BUNDLE", bundle_file)
+        assert _resolve_requests_verify() == bundle_file

tests/hermes_cli/test_auth_nous_provider.py

@@ -19,6 +19,12 @@ from hermes_cli.auth import AuthError, get_provider_auth_state, resolve_nous_run
 class TestResolveVerifyFallback:
     """Verify _resolve_verify falls back to True when CA bundle path doesn't exist."""
 
+    @pytest.fixture(autouse=True)
+    def _pin_platform_to_linux(self, monkeypatch):
+        """Pin sys.platform so the macOS certifi fallback doesn't alter the
+        generic "default trust" return value asserted by these tests."""
+        monkeypatch.setattr("sys.platform", "linux")
+
     def test_missing_ca_bundle_in_auth_state_falls_back(self):
         from hermes_cli.auth import _resolve_verify
 

tests/hermes_cli/test_auth_ssl_macos.py

@@ -0,0 +1,115 @@
+"""Tests for hermes_cli.auth._default_verify platform-aware fallback.
+
+On macOS with Homebrew Python, the system OpenSSL cannot locate the
+system trust store, so we explicitly load certifi's bundle. On other
+platforms we defer to httpx's own default (which itself uses certifi).
+
+Most tests use monkeypatching — no real SSL handshakes. A handful use
+an openssl-generated self-signed cert via the `real_bundle_file`
+fixture because `ssl.create_default_context(cafile=...)` parses the
+bundle and refuses stubs.
+"""
+
+import os
+import shutil
+import ssl
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+from hermes_cli.auth import _default_verify, _resolve_verify
+
+
+@pytest.fixture
+def real_bundle_file(tmp_path: Path) -> str:
+    """Return a path to a real openssl-generated self-signed cert.
+
+    Skips the test when the `openssl` binary isn't on PATH, so CI images
+    without it degrade gracefully instead of erroring out.
+    """
+    if shutil.which("openssl") is None:
+        pytest.skip("openssl binary not available")
+    cert = tmp_path / "ca.pem"
+    key = tmp_path / "key.pem"
+    result = subprocess.run(
+        [
+            "openssl", "req", "-x509", "-newkey", "rsa:2048",
+            "-keyout", str(key), "-out", str(cert),
+            "-sha256", "-days", "1", "-nodes",
+            "-subj", "/CN=test",
+        ],
+        capture_output=True,
+        timeout=10,
+    )
+    if result.returncode != 0:
+        pytest.skip(f"openssl failed: {result.stderr.decode('utf-8', 'ignore')[:200]}")
+    return str(cert)
+
+
+class TestDefaultVerify:
+    def test_returns_ssl_context_on_darwin(self, monkeypatch):
+        monkeypatch.setattr(sys, "platform", "darwin")
+        result = _default_verify()
+        assert isinstance(result, ssl.SSLContext)
+
+    def test_returns_true_on_linux(self, monkeypatch):
+        monkeypatch.setattr(sys, "platform", "linux")
+        assert _default_verify() is True
+
+    def test_returns_true_on_windows(self, monkeypatch):
+        monkeypatch.setattr(sys, "platform", "win32")
+        assert _default_verify() is True
+
+    def test_darwin_falls_back_to_true_when_certifi_missing(self, monkeypatch):
+        monkeypatch.setattr(sys, "platform", "darwin")
+
+        real_import = __import__
+
+        def fake_import(name, *args, **kwargs):
+            if name == "certifi":
+                raise ImportError("simulated missing certifi")
+            return real_import(name, *args, **kwargs)
+
+        monkeypatch.setattr("builtins.__import__", fake_import)
+        assert _default_verify() is True
+
+
+class TestResolveVerifyIntegration:
+    """_resolve_verify should defer to _default_verify in the no-CA path."""
+
+    def test_no_ca_uses_default_verify_on_darwin(self, monkeypatch):
+        monkeypatch.setattr(sys, "platform", "darwin")
+        for var in ("HERMES_CA_BUNDLE", "SSL_CERT_FILE", "REQUESTS_CA_BUNDLE"):
+            monkeypatch.delenv(var, raising=False)
+        result = _resolve_verify()
+        assert isinstance(result, ssl.SSLContext)
+
+    def test_no_ca_uses_default_verify_on_linux(self, monkeypatch):
+        monkeypatch.setattr(sys, "platform", "linux")
+        for var in ("HERMES_CA_BUNDLE", "SSL_CERT_FILE", "REQUESTS_CA_BUNDLE"):
+            monkeypatch.delenv(var, raising=False)
+        assert _resolve_verify() is True
+
+    def test_requests_ca_bundle_respected(self, monkeypatch, real_bundle_file):
+        for var in ("HERMES_CA_BUNDLE", "SSL_CERT_FILE"):
+            monkeypatch.delenv(var, raising=False)
+        monkeypatch.setenv("REQUESTS_CA_BUNDLE", real_bundle_file)
+        result = _resolve_verify()
+        assert isinstance(result, ssl.SSLContext)
+
+    def test_missing_ca_path_falls_back_to_default_verify(self, monkeypatch, tmp_path):
+        monkeypatch.setattr(sys, "platform", "linux")
+        monkeypatch.setenv("HERMES_CA_BUNDLE", str(tmp_path / "missing.pem"))
+        for var in ("SSL_CERT_FILE", "REQUESTS_CA_BUNDLE"):
+            monkeypatch.delenv(var, raising=False)
+        assert _resolve_verify() is True
+
+    def test_insecure_wins_over_everything(self, monkeypatch, tmp_path):
+        bundle = tmp_path / "ca.pem"
+        bundle.write_text("stub")
+        monkeypatch.setenv("HERMES_CA_BUNDLE", str(bundle))
+        assert _resolve_verify(insecure=True) is False