fix: 恢复V6原内容匹配数据库checksum

src/main/resources/db/migration/V6__add_printers_table.sql

@@ -1 +1,11 @@
--- V6: 已废弃，原功能已回滚
+-- 打印机表
+CREATE TABLE IF NOT EXISTS printers (
+    printer_id VARCHAR(36) PRIMARY KEY,
+    name VARCHAR(100) NOT NULL,
+    ip VARCHAR(50) NOT NULL,
+    port INTEGER DEFAULT 9100,
+    is_default INTEGER DEFAULT 0,
+    status INTEGER DEFAULT 1,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);