Refactor and remove sqlite and replace with MySQL

internal/storage/mysql/syndicate/create.go

@@ -0,0 +1,21 @@
+package storage
+
+import (
+	"database/sql"
+)
+
+func AddMemberToSyndicate(db *sql.DB, syndicateID, userID int) error {
+	_, err := db.Exec(`
+		INSERT INTO syndicate_members (syndicate_id, user_id, joined_at)
+		VALUES (?, ?, CURRENT_TIMESTAMP)
+	`, syndicateID, userID)
+	return err
+}
+
+func InviteUserToSyndicate(db *sql.DB, syndicateID, invitedUserID, senderID int) error {
+	_, err := db.Exec(`
+		INSERT INTO syndicate_invites (syndicate_id, invited_user_id, sent_by_user_id)
+		VALUES (?, ?, ?)
+	`, syndicateID, invitedUserID, senderID)
+	return err
+}