Add in-app Settings page for secrets; move Gmail creds out of source

- settings.py: JSON-on-volume store with env fallback; secrets never rendered.
- /settings page (⚙️ in nav) to set Gmail address + app password + reminder prefs;
  password fields are write-only (blank keeps existing).
- reminders.py reads Gmail creds from Settings instead of a hardcoded password
  (resolves #2 in code — note the old password is still in git history; rotate it).
- mac_notification no longer crashes off-macOS; FLASK_DEBUG gates debug (#7).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

reminders.py

@@ -7,26 +7,41 @@ from email.mime.multipart import MIMEMultipart
 from datetime import date, timedelta
 import calendar as cal_module
 from bills import load_bills
+from settings import get_setting
 
-EMAIL = "bonna61@gmail.com"
-APP_PASSWORD = "qowu zcff dbtk kqbs"
+
+def _gmail():
+    """Resolve Gmail creds + recipient from Settings (env-var fallback)."""
+    email = get_setting("gmail_address", env="GMAIL_ADDRESS", default="")
+    pw = get_setting("gmail_app_password", env="GMAIL_APP_PASSWORD", default="")
+    recipient = get_setting("reminder_recipient", default="") or email
+    return email, pw, recipient
 
 
 def send_email(subject, body_html, body_text):
+    email, pw, recipient = _gmail()
+    if not (email and pw):
+        print("Gmail not configured in Settings — skipping email reminder.")
+        return
     msg = MIMEMultipart("alternative")
     msg["Subject"] = subject
-    msg["From"] = f"Moon Household Budget <{EMAIL}>"
-    msg["To"] = EMAIL
+    msg["From"] = f"Moon Household Budget <{email}>"
+    msg["To"] = recipient
     msg.attach(MIMEText(body_text, "plain"))
     msg.attach(MIMEText(body_html, "html"))
     with smtplib.SMTP_SSL("smtp.gmail.com", 465) as server:
-        server.login(EMAIL, APP_PASSWORD)
-        server.sendmail(EMAIL, EMAIL, msg.as_string())
+        server.login(email, pw)
+        server.sendmail(email, recipient, msg.as_string())
 
 
 def mac_notification(title, message):
+    # macOS-only; no-op (don't crash) when osascript isn't available, e.g. in
+    # the Linux container.
     script = f'display notification "{message}" with title "{title}" sound name "Default"'
-    subprocess.run(["osascript", "-e", script])
+    try:
+        subprocess.run(["osascript", "-e", script], check=False)
+    except (FileNotFoundError, OSError):
+        pass
 
 
 def bills_due_in(days):