security(runtime_provider): close OLLAMA_API_KEY substring-leak sweep miss (#13522)

Two call sites still used a raw substring check to identify ollama.com:

  hermes_cli/runtime_provider.py:496:
      _is_ollama_url = "ollama.com" in base_url.lower()

  run_agent.py:6127:
      if fb_base_url_hint and "ollama.com" in fb_base_url_hint.lower() ...

Same bug class as GHSA-xf8p-v2cg-h7h5 (OpenRouter substring leak), which
was fixed in commit dbb7e00e via base_url_host_matches() across the
codebase. The earlier sweep missed these two Ollama sites. Self-discovered
during April 2026 security-advisory triage; filed as GHSA-76xc-57q6-vm5m.

Impact is narrow — requires a user with OLLAMA_API_KEY configured AND a
custom base_url whose path or look-alike host contains 'ollama.com'.
Users on default provider flows are unaffected. Filed as a draft advisory
to use the private-fork flow; not CVE-worthy on its own.

Fix is mechanical: replace substring check with base_url_host_matches
at both sites. Same helper the rest of the codebase uses.

Tests: 67 -> 71 passing. 7 new host-matcher cases in
tests/test_base_url_hostname.py (path injection, lookalike host,
localtest.me subdomain, ollama.ai TLD confusion, localhost, genuine
ollama.com, api.ollama.com subdomain) + 4 call-site tests in
tests/hermes_cli/test_runtime_provider_resolution.py verifying
OLLAMA_API_KEY is selected only when base_url actually targets
ollama.com.

Fixes GHSA-76xc-57q6-vm5m

hermes_cli/runtime_provider.py

@@ -492,8 +492,12 @@ def _resolve_openrouter_runtime(
     else:
         # Custom endpoint: use api_key from config when using config base_url (#1760).
         # When the endpoint is Ollama Cloud, check OLLAMA_API_KEY — it's
-        # the canonical env var for ollama.com authentication.
-        _is_ollama_url = "ollama.com" in base_url.lower()
+        # the canonical env var for ollama.com authentication. Match on
+        # HOST, not substring — a custom base_url whose path contains
+        # "ollama.com" (e.g. http://127.0.0.1/ollama.com/v1) or whose
+        # hostname is a look-alike (ollama.com.attacker.test) must not
+        # receive the Ollama credential. See GHSA-76xc-57q6-vm5m.
+        _is_ollama_url = base_url_host_matches(base_url, "ollama.com")
         api_key_candidates = [
             explicit_api_key,
             (cfg_api_key if use_config_base_url else ""),