feat(channel-donation): 채널 후원 기능 추가

docs/20260223_channel_donation_message_ddl.sql

@@ -0,0 +1,18 @@
+CREATE TABLE channel_donation_message
+(
+    id                 BIGINT AUTO_INCREMENT PRIMARY KEY COMMENT 'PK',
+    member_id          BIGINT     NOT NULL COMMENT '후원한 유저',
+    creator_id         BIGINT     NOT NULL COMMENT '후원 받은 채널 크리에이터',
+    can                INT        NOT NULL COMMENT '후원한 캔',
+    is_secret          TINYINT(1) NOT NULL DEFAULT 0 COMMENT '비밀후원 여부(false=0, true=1)',
+    additional_message TEXT       NULL COMMENT '추가 메시지',
+    created_at         TIMESTAMP  NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '생성 시각',
+    updated_at         TIMESTAMP  NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '수정 시각',
+    PRIMARY KEY (id),
+    KEY idx_channel_donation_message_creator_created_at (creator_id, created_at),
+    KEY idx_channel_donation_message_member (member_id),
+    CONSTRAINT fk_channel_donation_message_member
+        FOREIGN KEY (member_id) REFERENCES member (id),
+    CONSTRAINT fk_channel_donation_message_creator
+        FOREIGN KEY (creator_id) REFERENCES member (id)
+) COMMENT ='채널 후원 메시지';