fix(share): robust clipboard copy with an iOS-safe fallback

navigator.clipboard.writeText is intermittent on iOS Safari (bug 9: the
download share-link copy 'often does neither'). Add lib/clipboard.ts
copyText(): a gesture-safe execCommand path FIRST (before any await can
spend the transient user activation), async Clipboard API as fallback.
Migrate all five copy call sites to it.

frontend/src/components/DownloadCenter.tsx

@@ -31,6 +31,7 @@ import { useMe } from "../lib/useMe";
 import { api, type DownloadJob } from "../lib/api";
 import { invalidateDownloads } from "../lib/downloads";
 import { notify } from "../lib/notifications";
+import { copyText } from "../lib/clipboard";
 import { formatBytes, formatDuration, formatEta, formatSpeed } from "../lib/format";
 import { inputCls } from "./ui/form";
 
@@ -129,10 +130,9 @@ function displayUrl(url: string): string {
 function SourceRef({ url }: { url: string }) {
   const { t } = useTranslation();
   const copy = async () => {
-    try {
-      await navigator.clipboard.writeText(url);
+    if (await copyText(url)) {
       notify({ level: "success", message: t("downloads.source.copied") });
-    } catch {
+    } else {
       notify({ level: "error", message: t("downloads.source.copyFailed") });
     }
   };

frontend/src/components/GlassTuner.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useMemo, useState } from "react";
 import Overlay from "./Overlay";
+import { copyText } from "../lib/clipboard";
 import { usePrefs } from "./PrefsProvider";
 
 /**
@@ -205,11 +206,11 @@ export default function GlassTuner() {
     return lines.length ? `${scope} {\n${lines.join("\n")}\n}` : "/* all values at defaults */";
   }, [vars, palette, themeTick]);
 
-  function copy() {
-    navigator.clipboard?.writeText(cssOut).then(() => {
+  async function copy() {
+    if (await copyText(cssOut)) {
       setCopied(true);
       setTimeout(() => setCopied(false), 1200);
-    });
+    }
   }
 
   function persistOpen(v: boolean) {

frontend/src/components/SavedViewsWidget.tsx

@@ -20,6 +20,7 @@ import { CSS } from "@dnd-kit/utilities";
 import { api, getActiveAccount, type FeedFilters, type SavedView } from "../lib/api";
 import { filtersToParams, shareUrl } from "../lib/urlState";
 import { notify } from "../lib/notifications";
+import { copyText } from "../lib/clipboard";
 import { accountKey, LS, writeJSON } from "../lib/storage";
 import { useConfirm } from "./ConfirmProvider";
 
@@ -108,10 +109,9 @@ export default function SavedViewsWidget({
   }
 
   async function share(v: SavedView) {
-    try {
-      await navigator.clipboard.writeText(shareUrl(asFilters(v.filters)));
+    if (await copyText(shareUrl(asFilters(v.filters)))) {
       notify({ level: "success", message: t("views.shareCopied") });
-    } catch {
+    } else {
       notify({ level: "warning", message: t("sidebar.shareFailed") });
     }
   }

frontend/src/components/ShareDialog.tsx

@@ -6,6 +6,7 @@ import clsx from "clsx";
 import Modal from "./Modal";
 import { useConfirm } from "./ConfirmProvider";
 import { notify } from "../lib/notifications";
+import { copyText } from "../lib/clipboard";
 import { api, type DownloadJob, type ShareLink } from "../lib/api";
 import { inputCls, btnCls } from "./ui/form";
 const EXPIRY_DAYS = [null, 1, 7, 30] as const;
@@ -87,11 +88,10 @@ function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }
   const fullUrl = window.location.origin + link.url;
 
   const copy = async () => {
-    try {
-      await navigator.clipboard.writeText(fullUrl);
+    if (await copyText(fullUrl)) {
       setCopied(true);
       setTimeout(() => setCopied(false), 1500);
-    } catch {
+    } else {
       notify({ level: "error", message: t("downloads.share.copyFailed") });
     }
   };

frontend/src/components/Sidebar.tsx

@@ -5,6 +5,7 @@ import { Library, Pencil, Share2, SlidersHorizontal, User } from "lucide-react";
 import { api, type FeedFilters, type Tag } from "../lib/api";
 import { defaultLayout, type PanelLayout } from "../lib/panelLayout";
 import { shareUrl } from "../lib/urlState";
+import { copyText } from "../lib/clipboard";
 import { notify } from "../lib/notifications";
 import { useDebounced } from "../lib/useDebounced";
 import { clearedFilters, useActiveFilters } from "../lib/useActiveFilters";
@@ -125,10 +126,9 @@ export default function Sidebar({
   const active = activeCount > 0;
 
   async function shareView() {
-    try {
-      await navigator.clipboard.writeText(shareUrl(filters));
+    if (await copyText(shareUrl(filters))) {
       notify({ level: "success", message: t("sidebar.shareCopied") });
-    } catch {
+    } else {
       notify({ level: "warning", message: t("sidebar.shareFailed") });
     }
   }