feat(frontend): 广场搜索体验优化与切换tab重置筛选

- 智能体广场：切换 我的/广场/私密广场 时清空重置搜索/标签/排序/发布者筛选
- 通用搜索栏(TagSearchBar)：新增「搜索」按钮与回车立即触发(跳过防抖)、
  搜索中转圈提示，新增 hideTags / searchPlaceholder 选项
- 定时任务广场：新增客户端搜索(名称/摘要/创建者，兼容脱敏文本)
- agents 分页 hook 暴露 isFetching 以驱动搜索中状态

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/components/workspace/agents/agent-gallery.tsx

@@ -74,6 +74,7 @@ export function AgentGallery() {
     agents: mainAgents,
     total: mainTotal,
     isLoading: mainLoading,
+    isFetching: mainFetching,
   } = useAgentsPaginated({
     scope: mainScope,
     search,
@@ -89,6 +90,7 @@ export function AgentGallery() {
     agents: privateAgents,
     total: privateTotal,
     isLoading: isPrivateLoading,
+    isFetching: isPrivateFetching,
     error: privateError,
   } = usePrivateAgentsPaginated(privatePassword, {
     search,
@@ -315,9 +317,16 @@ export function AgentGallery() {
       {/* Tabs */}
       <Tabs
         value={activeTab}
-        onValueChange={(v) =>
-          setActiveTab(v as "all" | "mine" | "private")
-        }
+        onValueChange={(v) => {
+          setActiveTab(v as "all" | "mine" | "private");
+          // Each tab starts from a clean slate: switching tabs clears the
+          // keyword / tag / sort / publisher filters instead of carrying them
+          // over. The TagSearchBar's own input box is reset via its key below.
+          setSearch("");
+          setTagIds([]);
+          setSort("time_desc");
+          setPublisher(null);
+        }}
         className="flex flex-1 flex-col overflow-hidden"
       >
         <div className="mx-6 mt-4 flex flex-col gap-3">
@@ -351,7 +360,11 @@ export function AgentGallery() {
             </div>
           </div>
           <TagSearchBar
+            // Remount per tab so the internal keyword input / 展开 state also
+            // resets when the parent-owned filters are cleared on tab switch.
+            key={activeTab}
             targetType="agent"
+            searching={activeTab === "private" ? isPrivateFetching : mainFetching}
             onSearchChange={setSearch}
             tagIds={tagIds}
             onTagIdsChange={setTagIds}

frontend-web/src/components/workspace/tags/tag-search-bar.tsx

@@ -1,8 +1,9 @@
 "use client";
 
-import { CheckIcon, ChevronDownIcon, ChevronUpIcon, SearchIcon } from "lucide-react";
+import { CheckIcon, ChevronDownIcon, ChevronUpIcon, Loader2, SearchIcon } from "lucide-react";
 import { useEffect, useRef, useState, type ReactNode } from "react";
 
+import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { useI18n } from "@/core/i18n/hooks";
 import { useTags, type TagType } from "@/core/tags";
@@ -18,27 +19,42 @@ const COLLAPSE_THRESHOLD = 16;
  *
  * The name input is debounced (300ms) before ``onSearchChange`` fires, so the
  * caller can feed the value straight into a server-side query without a
- * request per keystroke.
+ * request per keystroke. Pressing Enter or clicking the 搜索 button flushes the
+ * pending debounce immediately, so users never wait on the timer.
+ *
+ * Pass ``searching`` while a query is in flight to show an inline spinner — it
+ * makes server-side searches feel responsive instead of looking like they kept
+ * the previous results.
  *
  * Tags are rendered inline as a multi-select chip row (instead of a dropdown):
  * "全部" is selected when no tag is picked, and any number of tags can be
  * toggled. Filtering is OR — a resource matches if it carries any picked tag.
- * When there are many tags the row collapses behind a 展开/收起 toggle.
+ * When there are many tags the row collapses behind a 展开/收起 toggle. Pass
+ * ``hideTags`` for resources without tags (e.g. the published-task plaza).
  */
 export function TagSearchBar({
   targetType,
   onSearchChange,
-  tagIds,
+  tagIds = [],
   onTagIdsChange,
   className,
   actions,
+  searching = false,
+  hideTags = false,
+  searchPlaceholder,
 }: {
   targetType: TagType;
   onSearchChange: (value: string) => void;
-  tagIds: string[];
-  onTagIdsChange: (value: string[]) => void;
+  tagIds?: string[];
+  onTagIdsChange?: (value: string[]) => void;
   className?: string;
   actions?: ReactNode;
+  /** Show an inline spinner while the caller's query is fetching. */
+  searching?: boolean;
+  /** Hide the tag chip row for resources that have no tags. */
+  hideTags?: boolean;
+  /** Override the search input placeholder. */
+  searchPlaceholder?: string;
 }) {
   const { t } = useI18n();
   const { data: tags } = useTags(targetType);
@@ -47,11 +63,21 @@ export function TagSearchBar({
   const [expanded, setExpanded] = useState(false);
   const cbRef = useRef(onSearchChange);
   cbRef.current = onSearchChange;
+  // Keep the pending debounce timer so an explicit search (Enter / 搜索 button)
+  // can cancel it and fire immediately instead of racing the 300ms delay.
+  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   useEffect(() => {
-    const id = setTimeout(() => cbRef.current(input.trim()), 300);
-    return () => clearTimeout(id);
+    timerRef.current = setTimeout(() => cbRef.current(input.trim()), 300);
+    return () => {
+      if (timerRef.current) clearTimeout(timerRef.current);
+    };
   }, [input]);
 
+  const flushSearch = () => {
+    if (timerRef.current) clearTimeout(timerRef.current);
+    cbRef.current(input.trim());
+  };
+
   const allTags = tags ?? [];
   const canCollapse = allTags.length > COLLAPSE_THRESHOLD;
   // When collapsed, always keep the selected tags visible so the active
@@ -62,7 +88,7 @@ export function TagSearchBar({
       : allTags;
 
   const toggleTag = (id: string) => {
-    onTagIdsChange(
+    onTagIdsChange?.(
       tagIds.includes(id) ? tagIds.filter((x) => x !== id) : [...tagIds, id],
     );
   };
@@ -75,8 +101,14 @@ export function TagSearchBar({
           <Input
             value={input}
             onChange={(e) => setInput(e.target.value)}
-            placeholder={t.adminTags.searchPlaceholder}
-            className="pl-8"
+            onKeyDown={(e) => {
+              if (e.key === "Enter") {
+                e.preventDefault();
+                flushSearch();
+              }
+            }}
+            placeholder={searchPlaceholder ?? t.adminTags.searchPlaceholder}
+            className={cn("pl-8", searching && "pr-9")}
             name="tag-search"
             // A `type="password"` field elsewhere on the page (e.g. the private
             // square access gate) makes browsers / password managers pick the
@@ -88,7 +120,24 @@ export function TagSearchBar({
             data-lpignore="true"
             data-form-type="other"
           />
+          {searching && (
+            <Loader2 className="text-muted-foreground absolute right-2.5 top-1/2 size-4 -translate-y-1/2 animate-spin" />
+          )}
         </div>
+        <Button
+          type="button"
+          variant="outline"
+          onClick={flushSearch}
+          className="shrink-0 gap-1.5"
+          title="搜索"
+        >
+          {searching ? (
+            <Loader2 className="size-4 animate-spin" />
+          ) : (
+            <SearchIcon className="size-4" />
+          )}
+          搜索
+        </Button>
         {actions && (
           <div className="flex w-full shrink-0 justify-end sm:w-auto">
             {actions}
@@ -96,11 +145,11 @@ export function TagSearchBar({
         )}
       </div>
 
-      {allTags.length > 0 && (
+      {!hideTags && allTags.length > 0 && (
         <div className="flex flex-wrap items-center gap-1.5">
           <button
             type="button"
-            onClick={() => onTagIdsChange([])}
+            onClick={() => onTagIdsChange?.([])}
             className={cn(
               "inline-flex items-center rounded-full border px-3 py-1 text-xs font-medium transition-all",
               tagIds.length === 0