Added STS profile persistence and policy parsing/enforcement (including load/save, upgrades, and expiry rescheduling) to the STS module.

Integrated STS capability handling and connection lifecycle hooks (ignore CAP DEL, trigger upgrades, reschedule on disconnect, new server fields).
Initialized and cleaned up STS state during startup/shutdown to persist policies across sessions.

src/common/zoitechat.h

@@ -514,6 +514,7 @@ typedef struct server
 	int joindelay_tag;				/* waiting before we send JOIN */
 	char hostname[128];				/* real ip number */
 	char servername[128];			/* what the server says is its name */
+	char sts_host[128];
 	char password[1024];
 	char nick[NICKLEN];
 	char linebuf[8704];				/* RFC says 512 chars including \r\n, IRCv3 message tags add 8191, plus the NUL byte */
@@ -588,6 +589,8 @@ typedef struct server
 	unsigned int have_sasl:1;		/* SASL capability */
 	unsigned int have_except:1;	/* ban exemptions +e */
 	unsigned int have_invite:1;	/* invite exemptions +I */
+	unsigned int sts_duration_seen:1;
+	unsigned int sts_upgrade_in_progress:1;
 	unsigned int have_cert:1;	/* have loaded a cert */
 	unsigned int use_who:1;			/* whether to use WHO command to get dcc_ip */
 	unsigned int sasl_mech;			/* mechanism for sasl auth */