Update: 将子项目从 submodule 转为完整内容

- 移除 GovAI, nomifun-tauri, 算力盒子 的 submodule 引用
- 添加所有子项目的完整源代码
- 保留原始 .git 为 .git.bak 备份

nomifun-tauri/crates/backend/nomifun-db/migrations/018_user_role.sql

@@ -0,0 +1,30 @@
+-- Migration 002: Add user role support
+--
+-- Single-tenant architecture: all tables retain tenant_id as extension point,
+-- but the first deployed system operates in single-tenant mode.
+--
+-- This migration adds role-based access control to the users table.
+
+------------------------------------------------------------------------
+-- Extend users table with role field
+------------------------------------------------------------------------
+
+ALTER TABLE users ADD COLUMN role TEXT NOT NULL DEFAULT 'user'
+    CHECK(role IN ('admin', 'user'));
+
+-- Create index for role-based queries
+CREATE INDEX IF NOT EXISTS idx_users_role ON users(role);
+
+------------------------------------------------------------------------
+-- Seed data: upgrade existing users to admin if they are the first user
+------------------------------------------------------------------------
+
+-- The first registered user (by created_at) becomes admin
+-- This handles the case where users existed before this migration
+UPDATE users
+SET role = 'admin'
+WHERE id = (SELECT id FROM users ORDER BY created_at ASC LIMIT 1);
+
+------------------------------------------------------------------------
+-- End of migration
+------------------------------------------------------------------------