feat(db): split migrations into dialect-specific sqlite and postgres packages

backend/plugins/drivers/driver_asynq_cron/migrations/sqlite/00001_initial.sql

@@ -0,0 +1,24 @@
+-- +goose Up
+-- +goose StatementBegin
+CREATE TABLE IF NOT EXISTS w_schedules (
+    id BIGINT PRIMARY KEY,
+    name VARCHAR(128) NOT NULL,
+    task_type VARCHAR(64) NOT NULL,
+    cron VARCHAR(64) NOT NULL,
+    payload TEXT,
+    is_active BOOLEAN NOT NULL DEFAULT 1,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+CREATE INDEX IF NOT EXISTS idx_w_schedules_is_active ON w_schedules (is_active);
+
+-- Seed initial cleanup task
+INSERT INTO w_schedules (id, name, task_type, cron, payload, is_active, created_at, updated_at)
+VALUES (1, '系统定期垃圾清理', 'system_cleanup', '0 3 * * *', '{}', 1, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
+ON CONFLICT (id) DO NOTHING;
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+DROP TABLE IF EXISTS w_schedules;
+-- +goose StatementEnd