feat: regex support in email allowlist

Each entry in email_allowlist.json is treated as a re.fullmatch pattern
(case-insensitive). Allows domain wildcards, plus-addressing, and any
variation expressible as a regex. Invalid patterns are logged and skipped.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/tools/notify.py

@@ -8,6 +8,7 @@ email_send uses the server SMTP config from .env (smtp_server, smtp_from_*).
 import asyncio
 import json
 import logging
+import re
 
 from config import settings
 from persona import get_user
@@ -15,11 +16,11 @@ from persona import get_user
 logger = logging.getLogger(__name__)
 
 
-def _email_allowlist(username: str) -> list[str]:
+def _load_allowlist(username: str) -> list[str]:
     """Load the per-user email allowlist. Returns empty list if not configured."""
     path = settings.home_root() / username / "email_allowlist.json"
     try:
-        return [a.lower().strip() for a in json.loads(path.read_text())]
+        return [str(p).strip() for p in json.loads(path.read_text()) if str(p).strip()]
     except FileNotFoundError:
         return []
     except Exception as e:
@@ -27,18 +28,30 @@ def _email_allowlist(username: str) -> list[str]:
         return []
 
 
+def _email_allowed(address: str, patterns: list[str]) -> bool:
+    """Return True if address matches any pattern (regex, case-insensitive full match)."""
+    addr = address.strip()
+    for pattern in patterns:
+        try:
+            if re.fullmatch(pattern, addr, re.IGNORECASE):
+                return True
+        except re.error:
+            logger.warning("invalid regex in email allowlist: %r", pattern)
+    return False
+
+
 async def email_send(to: str, subject: str, body: str) -> str:
     """Send an email via the server's configured SMTP account."""
     username = get_user()
-    allowlist = _email_allowlist(username)
+    allowlist = _load_allowlist(username)
 
     if not allowlist:
         return (
             "Email blocked — no allowlist configured. "
-            f"Add allowed addresses to home/{username}/email_allowlist.json as a JSON array."
+            f"Add allowed patterns to home/{username}/email_allowlist.json as a JSON array."
         )
-    if to.lower().strip() not in allowlist:
-        return f"Email blocked — {to} is not in the allowlist for {username}."
+    if not _email_allowed(to, allowlist):
+        return f"Email blocked — {to} does not match any allowed pattern for {username}."
 
     from email_utils import send_email
     ok = await asyncio.to_thread(