feat(ui): 强化 AI 工作中动效——构思占位/流式进度条/波动三点/转圈

- 动效基元：ai-dot 波动(三点竖跳)、ai-stream 不确定进度条、ai-breathe 呼吸微光（均带 reduced-motion 回退）
- ThinkingIndicator 升级为明显波动；新增 Spinner / StreamingBar / GenerationSkeleton 原子件；Button 加 loading 态
- 写作台：首 token 前正文区『AI 正在构思本章…』占位（补最大缺口，不再空白像卡死）+ 流式顶部进度条
- 整章重写流式进度条；续写/润色忙碌骨架 + 触发键转圈；生成器/角色/世界观改用 Button loading

apps/web/components/toolbox/GeneratorRunner.tsx

@@ -254,9 +254,9 @@ export function GeneratorRunner({
             onChange={(v) => setField(field.name, v)}
           />
         ))}
-        <Button type="submit" disabled={generating} variant="primary">
+        <Button type="submit" loading={generating} variant="primary">
           <Sparkles className="h-4 w-4" aria-hidden="true" />
-          {generating ? "生成中…" : "生成"}
+          生成
         </Button>
         {generating ? (
           <ThinkingIndicator
@@ -297,15 +297,14 @@ export function GeneratorRunner({
           {canIngest && gen.ingestStatus !== "conflict" ? (
             <Button
               onClick={() => void runIngest(false)}
-              disabled={ingesting || (!singleObject && selected.size === 0)}
+              loading={ingesting}
+              disabled={!singleObject && selected.size === 0}
               variant="outline"
             >
               <Database className="h-4 w-4" aria-hidden="true" />
-              {ingesting
-                ? "入库中…"
-                : singleObject
-                  ? `入库为规则至 ${table}`
-                  : `入库选中（${selected.size}）至 ${table}`}
+              {singleObject
+                ? `入库为规则至 ${table}`
+                : `入库选中（${selected.size}）至 ${table}`}
             </Button>
           ) : null}