fix: delete expired rules before insert to avoid UNIQUE constraint error

Expired rules with the same (container, destination, port, action) key
were blocking new rule creation because findExistingRule skips expired
rows but the UNIQUE constraint still enforces against them.

Author: tito

internal/greyproxy/crud.go

@@ -57,6 +57,14 @@ func CreateRule(db *DB, input RuleCreateInput) (*Rule, error) {
 		notes = sql.NullString{String: *input.Notes, Valid: true}
 	}
 
+	// Delete any expired rule with the same unique key so the insert won't conflict
+	db.WriteDB().Exec(
+		`DELETE FROM rules
+		 WHERE container_pattern = ? AND destination_pattern = ? AND port_pattern = ? AND action = ?
+		   AND expires_at IS NOT NULL AND expires_at <= datetime('now')`,
+		input.ContainerPattern, input.DestinationPattern, input.PortPattern, input.Action,
+	)
+
 	result, err := db.WriteDB().Exec(
 		`INSERT INTO rules (container_pattern, destination_pattern, port_pattern, rule_type, action, expires_at, created_by, notes)
 		 VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,