feat(knowledge): add retry endpoint and 20-char text name limit

Add POST /api/tenant/knowledge/items/retry/:id to re-queue failed parse
tasks, plus a 20-rune cap on text item names with matching frontend
validation. Wires the retry button into the knowledge table with a
colored status tag for clearer state feedback.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/lib/errors.ts

@@ -53,6 +53,7 @@ const errorMessageMap: Record<string, string> = {
   keyword_exists: "关键词已存在",
   keyword_limit_reached: "关键词数量已达当前套餐上限",
   question_limit_reached: "当前关键词下的问题数量已达上限",
+  knowledge_text_name_too_long: "文本名称不能超过 20 个字",
   brand_not_found: "品牌不存在或已删除",
   keyword_not_found: "关键词不存在或已删除",
   publish_cover_required: "当前选择的平台要求上传封面图，请先上传封面图",