加上登录和角色权限，并用 Vue 控制台区分用户与管理员。

Co-authored-by: Cursor <cursoragent@cursor.com>

app/schema_upgrade.py

@@ -0,0 +1,35 @@
+"""给已经上线的库补上认证字段。create_all 不会修改旧表。"""
+
+from sqlalchemy import inspect, text
+
+from app.database import engine
+
+
+def upgrade_schema() -> None:
+    inspector = inspect(engine)
+    if "users" not in inspector.get_table_names():
+        return
+    columns = {column["name"] for column in inspector.get_columns("users")}
+    statements: list[str] = []
+    if "username" not in columns:
+        statements.append("ALTER TABLE users ADD COLUMN username VARCHAR(32)")
+    if "password_hash" not in columns:
+        statements.append("ALTER TABLE users ADD COLUMN password_hash VARCHAR(255)")
+    if "role" not in columns:
+        statements.append("ALTER TABLE users ADD COLUMN role VARCHAR(16) DEFAULT 'user' NOT NULL")
+    if not statements and _has_username_index(inspector):
+        return
+    with engine.begin() as conn:
+        for statement in statements:
+            conn.execute(text(statement))
+        if not _has_username_index(inspector):
+            conn.execute(text("CREATE UNIQUE INDEX IF NOT EXISTS uq_users_username ON users (username)"))
+
+
+def _has_username_index(inspector) -> bool:
+    if "users" not in inspector.get_table_names():
+        return False
+    for index in inspector.get_indexes("users"):
+        if index.get("column_names") == ["username"] and index.get("unique"):
+            return True
+    return False