feat(auth,settings,tasks): add first-boot setup, real login/invites, full-page settings & admin views, multi-channel alarms, and fix null slice crashes

.env.example

@@ -4,5 +4,13 @@ DATA_DIR=/data
 DATABASE_URL=sqlite:///data/mindsift.db
 JWT_SECRET=change_this_to_a_secure_random_key_min_32_chars
 BASE_URL=http://localhost:8080
-ALLOW_REGISTRATION=true
+ALLOW_REGISTRATION=false
 LOG_LEVEL=info
+
+# Optional SMTP Server Configuration for Email Alarms (can also be set in Admin Settings UI)
+SMTP_HOST=
+SMTP_PORT=587
+SMTP_USER=
+SMTP_PASS=
+SMTP_FROM=noreply@mindsift.local
+SMTP_TLS=true