feat(config): add system configuration module (Phase 3)

Implement the complete erp-config crate with:
- Data dictionaries (CRUD + items management)
- Dynamic menus (tree structure with role filtering)
- System settings (hierarchical: platform > tenant > org > user)
- Numbering rules (concurrency-safe via PostgreSQL advisory_lock)
- Theme and language configuration (via settings store)
- 6 database migrations (dictionaries, menus, settings, numbering_rules)
- Frontend Settings page with 5 tabs (dictionary, menu, numbering, settings, theme)

Refactor: move RBAC functions (require_permission) from erp-auth to erp-core
to avoid cross-module dependencies.

Add 20 new seed permissions for config module operations.

crates/erp-auth/src/service/seed.rs

@@ -84,10 +84,27 @@ const DEFAULT_PERMISSIONS: &[(&str, &str, &str, &str, &str)] = &[
     ("position:read", "查看岗位", "position", "read", "查看岗位"),
     ("position:update", "编辑岗位", "position", "update", "编辑岗位"),
     ("position:delete", "删除岗位", "position", "delete", "删除岗位"),
+    // Config module permissions
+    ("dictionary:create", "创建字典", "dictionary", "create", "创建数据字典"),
+    ("dictionary:list", "查看字典", "dictionary", "list", "查看数据字典"),
+    ("dictionary:update", "编辑字典", "dictionary", "update", "编辑数据字典"),
+    ("dictionary:delete", "删除字典", "dictionary", "delete", "删除数据字典"),
+    ("menu:list", "查看菜单", "menu", "list", "查看菜单配置"),
+    ("menu:update", "编辑菜单", "menu", "update", "编辑菜单配置"),
+    ("setting:read", "查看配置", "setting", "read", "查看系统参数"),
+    ("setting:update", "编辑配置", "setting", "update", "编辑系统参数"),
+    ("numbering:create", "创建编号规则", "numbering", "create", "创建编号规则"),
+    ("numbering:list", "查看编号规则", "numbering", "list", "查看编号规则"),
+    ("numbering:update", "编辑编号规则", "numbering", "update", "编辑编号规则"),
+    ("numbering:generate", "生成编号", "numbering", "generate", "生成文档编号"),
+    ("theme:read", "查看主题", "theme", "read", "查看主题设置"),
+    ("theme:update", "编辑主题", "theme", "update", "编辑主题设置"),
+    ("language:list", "查看语言", "language", "list", "查看语言配置"),
+    ("language:update", "编辑语言", "language", "update", "编辑语言配置"),
 ];
 
 /// Indices of read-only permissions within DEFAULT_PERMISSIONS.
-const READ_PERM_INDICES: &[usize] = &[1, 5, 9, 11, 15, 19];
+const READ_PERM_INDICES: &[usize] = &[1, 5, 9, 11, 15, 19, 23, 24, 28, 29, 34, 38];
 
 /// Seed default auth data for a new tenant.
 ///