feat(reading-goals): 持久化阅读目标并收紧看板布局

migrations/001_reading_goals.sql

@@ -0,0 +1,20 @@
+-- 显式执行一次；只创建阅读目标相关表，不修改已有业务表。
+CREATE TABLE IF NOT EXISTS reading_goals (
+    id VARCHAR(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL,
+    name VARCHAR(60) NOT NULL,
+    start_date DATE NOT NULL,
+    end_date DATE NOT NULL,
+    sources JSON NOT NULL COMMENT '加入目标时的书单名称，不追踪书单后续变更',
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+    PRIMARY KEY (id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='阅读目标';
+
+CREATE TABLE IF NOT EXISTS reading_goal_books (
+    goal_id VARCHAR(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL,
+    book_id VARCHAR(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL,
+    PRIMARY KEY (goal_id, book_id),
+    CONSTRAINT fk_reading_goal_books_goal FOREIGN KEY (goal_id)
+        REFERENCES reading_goals (id) ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
+COMMENT='目标书籍成员；不关联书架表，避免移出书架时丢失目标成员';