Add managesieve (Sieve) support for remote accounts

When switching identities, the managesieve plugin still connected to
the default sieve server. Hook into managesieve_connect to redirect
the sieve connection to the remote account's server.

Adds sieve_host, sieve_port and sieve_auth columns to the database,
a Sieve section to the identity settings form, preconfig support for
sieve_host, and localized labels for all 7 languages.

SQL/mysql.initial.sql

@@ -37,6 +37,15 @@ CREATE TABLE IF NOT EXISTS `ident_switch`
 		smallint
 		NOT NULL
 		DEFAULT 1,
+	`sieve_host`
+		varchar(64),
+	`sieve_port`
+		int
+		CHECK(`sieve_port` > 0 AND `sieve_port` <= 65535),
+	`sieve_auth`
+		smallint
+		NOT NULL
+		DEFAULT 1,
 	`drafts_mbox`
 		varchar(64),
 	`sent_mbox`

SQL/mysql/2026021001.sql

@@ -0,0 +1,15 @@
+ALTER TABLE `ident_switch`
+	ADD `sieve_host` varchar(64) AFTER `smtp_auth`;
+
+ALTER TABLE `ident_switch`
+	ADD `sieve_port`
+		int
+		CHECK(`sieve_port` > 0 AND `sieve_port` <= 65535)
+		AFTER `sieve_host`;
+
+ALTER TABLE `ident_switch`
+	ADD `sieve_auth`
+		smallint
+		NOT NULL
+		DEFAULT 1
+		AFTER `sieve_port`;

SQL/postgres.initial.sql

@@ -38,6 +38,15 @@ CREATE TABLE ident_switch
 		smallint
 		NOT NULL
 		DEFAULT(1),
+	sieve_host
+		varchar(64),
+	sieve_port
+		integer
+		CHECK(sieve_port > 0 AND sieve_port <= 65535),
+	sieve_auth
+		smallint
+		NOT NULL
+		DEFAULT(1),
 	drafts_mbox
 		varchar(64),
 	sent_mbox

SQL/postgres/2026021001.sql

@@ -0,0 +1,13 @@
+ALTER TABLE ident_switch
+	ADD sieve_host varchar(64);
+
+ALTER TABLE ident_switch
+	ADD sieve_port
+		integer
+		CHECK(sieve_port > 0 AND sieve_port <= 65535);
+
+ALTER TABLE ident_switch
+	ADD sieve_auth
+		smallint
+		NOT NULL
+		DEFAULT(1);

SQL/sqlite.initial.sql

@@ -38,6 +38,15 @@ CREATE TABLE ident_switch
 		smallint
 		NOT NULL
 		DEFAULT 1,
+	sieve_host
+		varchar(64),
+	sieve_port
+		integer
+		CHECK(sieve_port > 0 AND sieve_port <= 65535),
+	sieve_auth
+		smallint
+		NOT NULL
+		DEFAULT 1,
 	drafts_mbox
 		varchar(64),
 	sent_mbox

SQL/sqlite/2026021001.sql

@@ -0,0 +1,13 @@
+ALTER TABLE ident_switch
+	ADD sieve_host varchar(64);
+
+ALTER TABLE ident_switch
+	ADD sieve_port
+		integer
+		CHECK(sieve_port > 0 AND sieve_port <= 65535);
+
+ALTER TABLE ident_switch
+	ADD sieve_auth
+		smallint
+		NOT NULL
+		DEFAULT 1;