fix(web): i18n fixes for sidebar and dropdown labels

- Add missing translation keys: skills.resultCount, skills.toolsetLabel
- Replace hardcoded "result(s)" and "toolset" with translated strings
- Fix stale useMemo in SkillsPage allCategories (missing `t` dependency)
  causing sidebar category names to stay in English after language switch

Made-with: Cursor

web/src/i18n/zh.ts

@@ -170,8 +170,10 @@ export const zh: Translations = {
     noSkills: "未找到技能。技能从 ~/.hermes/skills/ 加载",
     noSkillsMatch: "没有匹配的技能。",
     skillCount: "{count} 个技能",
+    resultCount: "{count} 个结果",
     noDescription: "暂无描述。",
     toolsets: "工具集",
+    toolsetLabel: "{name} 工具集",
     noToolsetsMatch: "没有匹配的工具集。",
     setupNeeded: "需要配置",
     disabledForCli: "CLI 已禁用",