Default to America/Phoenix and email-alert once when the session expires

Phoenix doesn't observe DST, so schedule times stay meaningful
year-round without needing a seasonal adjustment.

notify.py reuses lunch-notifier's existing Gmail-SMTP-with-app-password
pattern rather than adding a new notification channel. The alert fires
exactly once per expiry (not on every failed scheduled run while it's
down) via a dedupe flag in notify_state.json, reset the moment a fresh
session is successfully imported.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H6TgffxTvYhqxykAbVQg2v

automation.py

@@ -36,6 +36,7 @@ from datetime import datetime, timezone
 
 from playwright.sync_api import sync_playwright
 
+import notify
 import storage
 
 logger = logging.getLogger("massprice.automation")
@@ -79,9 +80,33 @@ def _is_logged_out(page):
     return "/Rule" not in page.url
 
 
+def _notify_session_expired_once():
+    """Send the email alert only on the first failure after the session
+    goes bad, not on every scheduled run that fails while it's down —
+    the flag resets when a fresh session is imported successfully."""
+    state = storage.load("notify_state.json", {})
+    if state.get("session_expired_notified"):
+        return
+    sent = notify.send_alert(
+        "MassPrice Scheduler: login session expired",
+        "The saved MassPrice session has expired or is missing. "
+        "Scheduled rule runs will keep failing until you log back in "
+        "via the Session page in the MassPrice Scheduler webui and "
+        "import a fresh cookie export.",
+    )
+    # Only mark as notified if the email actually sent — an unset/broken
+    # mail config shouldn't silently swallow the next attempt forever.
+    if sent:
+        storage.save(
+            "notify_state.json",
+            {"session_expired_notified": True, "notified_at": datetime.now(timezone.utc).isoformat()},
+        )
+
+
 def _ensure_authenticated(page):
     page.goto(f"{BASE_URL}/Rule/List")
     if _is_logged_out(page):
+        _notify_session_expired_once()
         raise AutomationError(
             "MassPrice session expired or missing — log in via the "
             "Session page and paste in a fresh cookie export."
@@ -264,5 +289,6 @@ def import_cookies(raw_text):
                     "itself, after finishing login, not from the login page."
                 )
             _save_state(context)
+            storage.save("notify_state.json", {"session_expired_notified": False})
         finally:
             browser.close()