HEL-144 返工A：四件事（改名/登录端标识/结账设置真保存/提醒回改）+ 迁移升为 7 + 移除废弃 B-44 前端样式测试

Co-authored-by: multica-agent <github@multica.ai>

src/bank_importer/db.py

@@ -798,6 +798,54 @@ MIGRATIONS: tuple[Migration, ...] = (
         DROP TABLE IF EXISTS manual_records;
         """,
     ),
+    Migration(
+        version=7,
+        name="0007_system_settings_and_reminders",
+        # System settings (closing day, global start date, auto-reminder) are
+        # persisted as a key/value table with an append-only change history
+        # (operator + before/after) for the audit requirement. Reminders are a
+        # separate append-only table so reminder history survives re-sends.
+        up="""
+        CREATE TABLE system_settings (
+            key TEXT PRIMARY KEY,
+            value TEXT NOT NULL,
+            updated_by INTEGER REFERENCES users (id),
+            updated_at TEXT NOT NULL
+        );
+
+        CREATE TABLE system_setting_changes (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            key TEXT NOT NULL,
+            before_value TEXT,
+            after_value TEXT NOT NULL,
+            actor_user_id INTEGER REFERENCES users (id),
+            actor_username TEXT,
+            created_at TEXT NOT NULL
+        );
+
+        CREATE TABLE reminders (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            company_id INTEGER NOT NULL REFERENCES companies (id),
+            kind TEXT NOT NULL,
+            content TEXT NOT NULL,
+            deadline TEXT,
+            source TEXT NOT NULL CHECK (source IN ('system', 'manual')),
+            status TEXT NOT NULL DEFAULT 'unread'
+                CHECK (status IN ('unread', 'done')),
+            actor_user_id INTEGER REFERENCES users (id),
+            actor_username TEXT,
+            created_at TEXT NOT NULL
+        );
+
+        CREATE INDEX idx_reminders_company ON reminders (company_id);
+        """,
+        down="""
+        DROP INDEX IF EXISTS idx_reminders_company;
+        DROP TABLE IF EXISTS reminders;
+        DROP TABLE IF EXISTS system_setting_changes;
+        DROP TABLE IF EXISTS system_settings;
+        """,
+    ),
 )