webui: always show RSS Add button + live rule match preview

- Article Add button now shows whenever the item has any source
  (magnet, enclosure, or a plain <link>/Atom href), and the manual
  download falls back to the link URL. Fixes missing + on feeds that
  only provide a <link> to the torrent.
- The rule editor now shows a live "current matches" list that updates
  as you type the filters / toggle regex / pick feeds, mirroring the
  daemon's matcher, with grabbed items dimmed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/js/app.js

@@ -980,7 +980,7 @@ async function renderRssView(host, seq) {
         ${articles.map((a, i) => `<tr style="${a.isRead ? 'opacity:.5' : ''}">
           <td class="dim">${f.esc(a.feed)}</td><td>${f.esc(a.title)}</td>
           <td class="num">${a.size ? f.bytes(a.size) : '—'}</td><td class="num dim">${f.esc(a.pubDate || '')}</td>
-          <td>${(a.magnet || a.torrentUrl)
+          <td>${(a.magnet || a.torrentUrl || a.link)
             ? `<button class="btn dl-art" data-art="${i}"${a.grabbed ? ' disabled' : ''}>${a.grabbed ? '✓ Added' : '＋ Add'}</button>`
             : '<span class="faint">—</span>'}</td></tr>`).join('')}
         </tbody></table>` : '<div class="dim">No articles yet.</div>'}
@@ -1010,7 +1010,7 @@ async function renderRssView(host, seq) {
   }));
   host.querySelectorAll('.dl-art').forEach((b) => b.addEventListener('click', () => guard(async () => {
     const a = articles[+b.dataset.art];
-    await api.rssDownload({ magnet: a.magnet || '', torrentUrl: a.torrentUrl || '', key: a.key || '' });
+    await api.rssDownload({ magnet: a.magnet || '', torrentUrl: a.torrentUrl || a.link || '', key: a.key || '' });
     b.textContent = '✓ Added'; b.disabled = true;
   }, 'Failed to add torrent')));
   host.querySelectorAll('[data-rule-edit]').forEach((b) => b.addEventListener('click', () =>
@@ -1064,7 +1064,9 @@ function openRuleEditor(rule, feeds) {
       <label><input type="checkbox" id="rEnabled" ${r.enabled ? 'checked' : ''}> Enabled</label>
       <label><input type="checkbox" id="rRegex" ${r.useRegex ? 'checked' : ''}> Use regex</label>
       <label><input type="checkbox" id="rPaused" ${r.addPaused ? 'checked' : ''}> Add paused</label>
-    </div>`,
+    </div>
+    <div class="field" style="margin-top:6px"><label>Current matches <span id="rMatchCount" class="dim"></span></label>
+      <div id="rMatches" class="rule-matches"></div></div>`,
     [{ label: 'Cancel', act: closeModal }, {
       label: 'Save', primary: true, act: () => guard(async () => {
         const name = document.getElementById('rName').value.trim();
@@ -1084,9 +1086,48 @@ function openRuleEditor(rule, feeds) {
         renderView();
       }, 'Failed to save rule'),
     }]);
+
+  // Live preview of which current articles this rule matches.
+  const allArticles = (feeds || []).flatMap((fd) => fd.articles.map((a) => ({ title: a.title, feed: fd.name, grabbed: a.grabbed })));
+  const updateMatches = () => {
+    const opts = {
+      must: document.getElementById('rMust').value.trim(),
+      mustNot: document.getElementById('rMustNot').value.trim(),
+      regex: document.getElementById('rRegex').checked,
+      feeds: [...document.querySelectorAll('.rule-feeds input:checked')].map((c) => c.value),
+    };
+    const matches = allArticles.filter((a) => ruleMatchesArticle(opts, a.feed, a.title));
+    document.getElementById('rMatchCount').textContent = `— ${matches.length} of ${allArticles.length} article(s)`;
+    const box = document.getElementById('rMatches');
+    box.innerHTML = matches.length
+      ? matches.slice(0, 50).map((a) => `<div class="match-row${a.grabbed ? ' grabbed' : ''}">
+          <span class="dim">${f.esc(a.feed)}</span> ${f.esc(a.title)}${a.grabbed ? ' <span class="faint">(grabbed)</span>' : ''}</div>`).join('')
+        + (matches.length > 50 ? `<div class="dim" style="padding:4px">…and ${matches.length - 50} more</div>` : '')
+      : '<div class="dim" style="padding:4px">No current articles match.</div>';
+  };
+  ['rMust', 'rMustNot'].forEach((id) => document.getElementById(id).addEventListener('input', updateMatches));
+  document.getElementById('rRegex').addEventListener('change', updateMatches);
+  document.querySelectorAll('.rule-feeds input').forEach((c) => c.addEventListener('change', updateMatches));
+  updateMatches();
   setTimeout(() => document.getElementById(rule ? 'rMust' : 'rName')?.focus(), 0);
 }
 
+// Client-side mirror of the daemon's rule matcher (for live preview).
+function ruleMatchesArticle(opts, feedName, title) {
+  if (opts.feeds && opts.feeds.length && !opts.feeds.includes(feedName)) return false;
+  if (opts.regex) {
+    try {
+      if (opts.must && !new RegExp(opts.must, 'i').test(title)) return false;
+      if (opts.mustNot && new RegExp(opts.mustNot, 'i').test(title)) return false;
+    } catch (e) { return false; }  // invalid regex matches nothing
+  } else {
+    const t = title.toLowerCase();
+    if (opts.must && !t.includes(opts.must.toLowerCase())) return false;
+    if (opts.mustNot && t.includes(opts.mustNot.toLowerCase())) return false;
+  }
+  return true;
+}
+
 function renderRule(r) {
   return `<div class="rule ${r.enabled ? '' : 'off'}">
     <div class="rule-head">