feat(canvas): 画布工作区 - 整合侧栏与风格预设并修复提示词回填

选择性整合 #547，保留主分支节点与工具条设计。新增默认折叠的节点、资产、任务和历史面板，风格与预设保留在节点内，移除重复入口。

补齐工具权限、提示词解析、资源引用保护及数据库迁移，修复提示词清空和连续编辑后的生成配置同步。

验证：前端全量 1925 项测试、构建、类型检查及 lint 通过；后端 go test ./... 通过。真实模型、PostgreSQL 实库与登录态页面验收仍待进行。

Refs #547

Co-authored-by: bensharp <bensharp@qq.com>

web/src/components/canvas/canvas-toolbar.tsx

@@ -51,6 +51,7 @@ export function CanvasToolbar({
     onSaveAppearanceDefault,
     onBackgroundModeChange,
     onShowImageInfoChange,
+    onOpenWorkspace,
     onOpenMyAssets,
     onOpenProjectCharacters,
 }: {
@@ -86,6 +87,7 @@ export function CanvasToolbar({
     onSaveAppearanceDefault: (appearance: CanvasAppearance) => void;
     onBackgroundModeChange: (mode: CanvasBackgroundMode) => void;
     onShowImageInfoChange: (show: boolean) => void;
+    onOpenWorkspace?: () => void;
     onOpenMyAssets: () => void;
     onOpenProjectCharacters: () => void;
 }) {
@@ -150,7 +152,8 @@ export function CanvasToolbar({
         onChooseStyle,
         onOpenDirector,
         onUpload,
-        onOpenMyAssets,
+        onOpenWorkspace,
+    onOpenMyAssets,
         onOpenProjectCharacters,
         onBackgroundModeChange,
         onShowImageInfoChange,