fix(ui): stabilize issue search URL sync and debounce query execution

ui/src/components/IssuesList.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useDeferredValue, useMemo, useState, useCallback, useRef } from "react";
+import { useEffect, useMemo, useState, useCallback, useRef } from "react";
 import { Link } from "@/lib/router";
 import { useQuery } from "@tanstack/react-query";
 import { useDialog } from "../context/DialogContext";
@@ -175,8 +175,19 @@ export function IssuesList({
   const [assigneePickerIssueId, setAssigneePickerIssueId] = useState<string | null>(null);
   const [assigneeSearch, setAssigneeSearch] = useState("");
   const [issueSearch, setIssueSearch] = useState(initialSearch ?? "");
-  const deferredIssueSearch = useDeferredValue(issueSearch);
-  const normalizedIssueSearch = deferredIssueSearch.trim();
+  const [debouncedIssueSearch, setDebouncedIssueSearch] = useState(issueSearch);
+  const normalizedIssueSearch = debouncedIssueSearch.trim();
+
+  useEffect(() => {
+    setIssueSearch(initialSearch ?? "");
+  }, [initialSearch]);
+
+  useEffect(() => {
+    const timeoutId = window.setTimeout(() => {
+      setDebouncedIssueSearch(issueSearch);
+    }, 300);
+    return () => window.clearTimeout(timeoutId);
+  }, [issueSearch]);
 
   // Reload view state from localStorage when company changes (scopedKey changes).
   const prevScopedKey = useRef(scopedKey);

ui/src/pages/Issues.tsx

@@ -22,13 +22,19 @@ export function Issues() {
   const handleSearchChange = useCallback((search: string) => {
     clearTimeout(debounceRef.current);
     debounceRef.current = setTimeout(() => {
+      const trimmedSearch = search.trim();
+      const currentSearch = new URLSearchParams(window.location.search).get("q") ?? "";
+      if (currentSearch === trimmedSearch) return;
+
       const url = new URL(window.location.href);
-      if (search.trim()) {
-        url.searchParams.set("q", search.trim());
+      if (trimmedSearch) {
+        url.searchParams.set("q", trimmedSearch);
       } else {
         url.searchParams.delete("q");
       }
-      window.history.replaceState(null, "", url);
+
+      const nextUrl = `${url.pathname}${url.search}${url.hash}`;
+      window.history.replaceState(window.history.state, "", nextUrl);
     }, 300);
   }, []);