fix(security): redact credential-bearing URLs and PII from logs (#4750)

* fix(security): redact credential-bearing URLs and PII from logs

Several log statements emitted sensitive data in clear text:

- model_routes / chat_routes / contacts_routes logged endpoint URLs raw.
  Admin-configured URLs can embed credentials in userinfo or query
  (e.g. https://user:pass@host, ?api_key=...). Route them through a
  shared core.log_safety.redact_url() that drops userinfo/query/fragment.
- note_routes / task_scheduler logged operator email addresses (smtp_user,
  recipient). Replaced with presence booleans, which keeps the diagnostic
  ("why didn't this send") without writing PII to logs.

model_routes already had a local redactor on its HTTPStatusError branch;
the generic except branch was missed, so reuse the existing helper there.

Clears CodeQL py/clear-text-logging-sensitive-data alerts 264, 317, 324,
325, 343, 344, 528.

* fix(security): re-bracket IPv6 hosts and single-source the URL redactor

Address review on #4750:
- redact_url now re-brackets IPv6 literals so host:port stays
  unambiguous (https://[2001:db8::1]:8443/v1, not the bracket-less
  ambiguous form).
- point model_routes._redact_url_for_log at the shared helper so the
  two redactors are single-sourced (also picks up the IPv6 fix).

routes/model_routes.py

@@ -17,6 +17,7 @@ from fastapi import APIRouter, HTTPException, Form, Query, Body, Request, Respon
 from pydantic import BaseModel
 from fastapi.responses import StreamingResponse
 from core.database import SessionLocal, ModelEndpoint, Session as DbSession
+from core.log_safety import redact_url as _redact_url_for_log
 from core.middleware import require_admin
 from src.llm_core import _detect_provider, _host_match, ANTHROPIC_MODELS
 from src.tls_overrides import llm_verify
@@ -582,18 +583,6 @@ def _safe_build_headers(api_key: Optional[str], base_url: str) -> dict:
         return {"Authorization": f"Bearer {api_key}"} if api_key else {}
 
 
-def _redact_url_for_log(url: str) -> str:
-    """Return a URL safe for logs by removing userinfo and query/fragment."""
-    try:
-        parsed = urlparse(url or "")
-        host = parsed.hostname or ""
-        if parsed.port:
-            host = f"{host}:{parsed.port}"
-        return urlunparse((parsed.scheme, host, parsed.path, "", "", ""))
-    except Exception:
-        return "<endpoint>"
-
-
 def _is_discovery_only_provider(provider: str) -> bool:
     return provider == "chatgpt-subscription"
 
@@ -810,9 +799,9 @@ def _probe_endpoint(base_url: str, api_key: str = None, timeout: int = 5) -> Lis
         logger.warning("Failed to probe %s: %s", _redact_url_for_log(url), e)
     except Exception as e:
         if api_key:
-            logger.warning(f"Failed to probe {url} with API key: {e}")
+            logger.warning("Failed to probe %s with API key: %s", _redact_url_for_log(url), e)
             return []
-        logger.warning(f"Failed to probe {url}: {e}")
+        logger.warning("Failed to probe %s: %s", _redact_url_for_log(url), e)
 
     # Older Ollama builds and some proxies expose native /api/tags even when
     # the OpenAI-compatible /v1/models path is unavailable.