fix(closet_llm): reject non-http(s) endpoints

LLMConfig accepted any URL scheme from LLM_ENDPOINT / --endpoint,
so a misconfigured endpoint such as file:///etc/passwd would be
passed straight to urllib.request.urlopen. Validate the scheme at
construction time and raise ValueError on anything other than
http/https, preserving the "privacy by architecture" guarantee.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mempalace/closet_llm.py

@@ -40,6 +40,7 @@ import json
 import os
 import re
 import time
+import urllib.parse
 import urllib.request
 import urllib.error
 from datetime import datetime
@@ -101,6 +102,14 @@ class LLMConfig:
         self.endpoint = (endpoint or os.environ.get("LLM_ENDPOINT", "")).rstrip("/")
         self.key = key or os.environ.get("LLM_KEY", "")
         self.model = model or os.environ.get("LLM_MODEL", "")
+        if self.endpoint:
+            # Privacy-by-architecture: reject file:// and other non-HTTP schemes
+            # so a misconfigured endpoint cannot exfiltrate local files.
+            scheme = urllib.parse.urlparse(self.endpoint).scheme.lower()
+            if scheme not in ("http", "https"):
+                raise ValueError(
+                    f"LLM_ENDPOINT must use http:// or https:// (got scheme {scheme!r})"
+                )
 
     def missing(self) -> list:
         missing = []