feat(schema): v19 卡片/分组组合表与迁移回填

- 新增 card / card_group：卡片只存标题与顺序，内容由勾选分组组成，支持混合格式
- v18→v19 迁移：按现有 section_block 回填卡片与分组勾选（card-<section>）
- 新库 seed 完成后同样回填，旧界面暂不受影响
- 测试 59 passed（含 15→19 迁移）

src/db/mod.rs

@@ -600,8 +600,9 @@ mod tests {
         let fresh = Connection::open_in_memory().expect("内存库应能打开");
         fresh
             .execute_batch(
-                "CREATE TABLE node (key TEXT PRIMARY KEY, parent_key TEXT, kind TEXT, view_mode TEXT);
+                "CREATE TABLE node (key TEXT PRIMARY KEY, parent_key TEXT, title TEXT, kind TEXT, view_mode TEXT);
                  CREATE TABLE entry (key TEXT PRIMARY KEY, node_key TEXT NOT NULL, name TEXT NOT NULL);
+                 CREATE TABLE section_block (id INTEGER PRIMARY KEY, node_key TEXT NOT NULL, title TEXT, preview_limit INTEGER, sort INTEGER NOT NULL DEFAULT 0);
                  PRAGMA user_version = 15;",
             )
             .expect("应能造出 v15 老库");

src/db/schema.rs

@@ -141,6 +141,44 @@ CREATE TABLE IF NOT EXISTS audit (
     target TEXT,
     detail TEXT
 );
+
+-- ========== v19：首页卡片（展示层组合） ==========
+
+-- 一张卡片 = 标题 + 顺序；内容由 card_group 勾选分组组成，卡片不拥有数据
+CREATE TABLE IF NOT EXISTS card (
+    id    INTEGER PRIMARY KEY AUTOINCREMENT,
+    key   TEXT NOT NULL UNIQUE,
+    title TEXT NOT NULL,
+    sort  INTEGER NOT NULL DEFAULT 0
+);
+
+-- 卡片包含哪些分组（可混合格式），每个分组可单独设预览条数
+CREATE TABLE IF NOT EXISTS card_group (
+    card_id       INTEGER NOT NULL REFERENCES card(id) ON DELETE CASCADE,
+    group_key     TEXT NOT NULL REFERENCES node(key) ON DELETE CASCADE ON UPDATE CASCADE,
+    sort          INTEGER NOT NULL DEFAULT 0,
+    preview_limit INTEGER,
+    PRIMARY KEY (card_id, group_key)
+);
+"#;
+
+/// 把老的「分区 → 一个展示块」迁移成「卡片 → 多个分组」。
+const BACKFILL_CARDS_SQL: &str = r#"
+INSERT OR IGNORE INTO card (key, title, sort)
+SELECT 'card-' || COALESCE(p.key, n.key),
+       COALESCE(b.title, COALESCE(p.title, n.title)),
+       MIN(b.sort)
+FROM section_block b
+JOIN node n ON n.key = b.node_key
+LEFT JOIN node p ON p.key = n.parent_key
+GROUP BY COALESCE(p.key, n.key);
+
+INSERT OR IGNORE INTO card_group (card_id, group_key, sort, preview_limit)
+SELECT c.id, b.node_key, b.sort, b.preview_limit
+FROM section_block b
+JOIN node n ON n.key = b.node_key
+LEFT JOIN node p ON p.key = n.parent_key
+JOIN card c ON c.key = 'card-' || COALESCE(p.key, n.key);
 "#;
 
 /// v16 → v17：条目加 `updated_at`（乐观锁），新增审计表。
@@ -172,6 +210,24 @@ WHERE kind = 'section' AND key IN (
 );
 "#;
 
+/// v18 → v19：首页卡片改为「卡片 + 勾选分组」。
+const V19_SQL: &str = r#"
+CREATE TABLE IF NOT EXISTS card (
+    id    INTEGER PRIMARY KEY AUTOINCREMENT,
+    key   TEXT NOT NULL UNIQUE,
+    title TEXT NOT NULL,
+    sort  INTEGER NOT NULL DEFAULT 0
+);
+
+CREATE TABLE IF NOT EXISTS card_group (
+    card_id       INTEGER NOT NULL REFERENCES card(id) ON DELETE CASCADE,
+    group_key     TEXT NOT NULL REFERENCES node(key) ON DELETE CASCADE ON UPDATE CASCADE,
+    sort          INTEGER NOT NULL DEFAULT 0,
+    preview_limit INTEGER,
+    PRIMARY KEY (card_id, group_key)
+);
+"#;
+
 /// v15 → v16 的增量（老库升级用；新库直接走 SCHEMA_SQL）。
 const V16_SQL: &str = r#"
 CREATE TABLE IF NOT EXISTS admin (
@@ -213,7 +269,7 @@ pub struct SeedReport {
 ///
 /// 从 v16 起有了第一套迁移：`migrate` 会把老库逐级升上来，
 /// 只有「比程序更新」或「没有迁移路径」的版本才拒绝启动。
-pub const SCHEMA_VERSION: i64 = 18;
+pub const SCHEMA_VERSION: i64 = 19;
 
 fn current_version(conn: &Connection) -> Result<i64, StashError> {
     conn.pragma_query_value(None, "user_version", |row| row.get(0))
@@ -262,6 +318,12 @@ pub fn migrate(conn: &Connection) -> Result<i64, StashError> {
         version = 18;
     }
 
+    if version == 18 {
+        conn.execute_batch(V19_SQL).map_err(map_error)?;
+        conn.execute_batch(BACKFILL_CARDS_SQL).map_err(map_error)?;
+        version = 19;
+    }
+
     conn.pragma_update(None, "user_version", version)
         .map_err(map_error)?;
 
@@ -371,6 +433,9 @@ pub fn seed(conn: &mut Connection) -> Result<SeedReport, StashError> {
         report.blocks += 1;
     }
 
+    // 老结构（分区 → 展示块）同步生成卡片，保证新首页立刻有内容
+    tx.execute_batch(BACKFILL_CARDS_SQL).map_err(map_error)?;
+
     tx.commit().map_err(map_error)?;
 
     Ok(report)