Add background mail checking and new mail notifications

SQL/mysql/2026021002.sql

@@ -0,0 +1,30 @@
+ALTER TABLE `ident_switch`
+	ADD `notify_check`
+		smallint
+		NOT NULL
+		DEFAULT 1
+		AFTER `sieve_auth`;
+
+ALTER TABLE `ident_switch`
+	ADD `notify_basic`
+		smallint
+		DEFAULT NULL
+		AFTER `notify_check`;
+
+ALTER TABLE `ident_switch`
+	ADD `notify_sound`
+		smallint
+		DEFAULT NULL
+		AFTER `notify_basic`;
+
+ALTER TABLE `ident_switch`
+	ADD `notify_desktop`
+		smallint
+		DEFAULT NULL
+		AFTER `notify_sound`;
+
+ALTER TABLE `ident_switch`
+	ADD `notify_sound_url`
+		varchar(255)
+		DEFAULT NULL
+		AFTER `notify_desktop`;