Show the manual sync command it will actually run, and guard --delete

The preview ended in the literal text "…src host:dst", so the one thing worth
checking before pressing Run — the real source and destination, and which of
them has the trailing slash — was the one thing never shown. --delete sat
unmarked among nine checkboxes with no confirmation on a card that can remove
data on the far host. Confirm fires only for --delete without --dry-run, so it
stays worth reading.

Plugin/unraid/pages/rsync.php

@@ -186,7 +186,7 @@ require_once dirname(__DIR__) . '/include/ai_chat.php';
       <div>
         <div class="vv-ms-lbl" style="margin-bottom:5px;">Local source</div>
         <div style="display:flex;gap:5px;align-items:center;margin-bottom:4px;">
-          <input class="vv-ms-inp" id="vv-ms-local" type="text" placeholder="/mnt/user/…"
+          <input class="vv-ms-inp" id="vv-ms-local" type="text" placeholder="/mnt/user/…" oninput="vvMsUpdatePreview()"
                  style="flex:1;min-width:0;" onkeydown="if(event.key==='Enter')vvMsBrowseLocal()">
           <button onclick="vvMsLocalNavUp()" title="Parent"
                   style="background:#111;border:1px solid #222;color:#555;border-radius:3px;
@@ -212,14 +212,14 @@ require_once dirname(__DIR__) . '/include/ai_chat.php';
           </div>
           <div style="flex:0 1 80px;">
             <div class="vv-ms-lbl" style="margin-bottom:3px;">User</div>
-            <select class="vv-ms-sel" id="vv-ms-user">
+            <select class="vv-ms-sel" id="vv-ms-user" onchange="vvMsUpdatePreview()">
               <option value="root">root</option>
             </select>
           </div>
         </div>
         <div class="vv-ms-lbl" style="margin-bottom:5px;">Remote path</div>
         <div style="display:flex;gap:5px;align-items:center;margin-bottom:4px;">
-          <input class="vv-ms-inp" id="vv-ms-rpath" type="text" placeholder="/mnt/user/…"
+          <input class="vv-ms-inp" id="vv-ms-rpath" type="text" placeholder="/mnt/user/…" oninput="vvMsUpdatePreview()"
                  style="flex:1;min-width:0;" onkeydown="if(event.key==='Enter')vvMsBrowse()">
           <button onclick="vvMsNavUp()" title="Parent"
                   style="background:#111;border:1px solid #222;color:#555;border-radius:3px;
@@ -256,8 +256,13 @@ require_once dirname(__DIR__) . '/include/ai_chat.php';
         <span style="font-size:9px;color:#2a2a2a;flex-shrink:0;">rsync</span>
         <span id="vv-ms-flags-preview"></span>
         <span id="vv-ms-bwlimit-preview" style="color:#2e4e2e;"></span>
-        <span style="color:#2a2a2a;">…src host:dst</span>
       </div>
+      <div style="margin-top:3px;background:#080808;border:1px solid #181818;border-radius:3px;
+                  padding:4px 8px;font-family:monospace;font-size:10px;color:#4a6a8a;
+                  word-break:break-all;" id="vv-ms-target-preview"></div>
+      <div id="vv-ms-delete-warn" style="display:none;margin-top:3px;background:#1a0d0d;
+                  border:1px solid #3a1a1a;border-radius:3px;padding:4px 8px;font-size:10px;
+                  color:#ef5350;"></div>
     </div>
 
     <!-- BW limit + SSH key -->
@@ -1660,6 +1665,8 @@ function vvMsHostChanged() {
   const host = _vvMsHosts.find(h => h.slot === slot);
   const stat = document.getElementById('vv-ms-host-status');
 
+  vvMsUpdatePreview();   // the destination just changed, so the command shown must too
+
   if (!host) { stat.textContent = ''; return; }
 
   const onlineTxt = host.online === null ? 'status unknown'
@@ -1720,6 +1727,14 @@ function vvMsBrowse() {
     });
 }
 
+// The whole command, with the real paths in it, not "…src host:dst".
+//
+// Two reasons it has to resolve rather than gesture. The first is the trailing slash: this card
+// already warns that "/" means contents and no "/" means the folder, and a hint under a text box
+// is not where anyone looks at the moment they press Run — in the command it is unmissable. The
+// second is --delete, which is one checkbox among nine and is the only one that removes data at
+// the far end. Seeing it sit next to the actual destination is the difference between reading a
+// flag and understanding a consequence.
 function vvMsUpdatePreview() {
   const flags = Array.from(document.querySelectorAll('#vv-ms-card input[data-flag]:checked'))
                      .map(el => el.dataset.flag).join(' ');
@@ -1728,6 +1743,31 @@ function vvMsUpdatePreview() {
   const bwPrev= document.getElementById('vv-ms-bwlimit-preview');
   if (prev)  prev.textContent  = flags || '(none)';
   if (bwPrev) bwPrev.textContent = bw > 0 ? '--bwlimit=' + bw : '';
+
+  const local = document.getElementById('vv-ms-local')?.value.trim() || '';
+  const rpath = document.getElementById('vv-ms-rpath')?.value.trim() || '';
+  const user  = document.getElementById('vv-ms-user')?.value || 'root';
+  const hostEl = document.getElementById('vv-ms-host');
+  const hostTxt = hostEl && hostEl.selectedIndex >= 0
+                ? (hostEl.options[hostEl.selectedIndex].textContent || '').trim() : '';
+  const tgt = document.getElementById('vv-ms-target-preview');
+  if (tgt) {
+    tgt.textContent = (local || '<source>') + '  ' + user + '@' + (hostTxt || '<host>') + ':' + (rpath || '<dest>');
+  }
+
+  // Destructive styling follows the checkbox, so the warning cannot be left on screen after the
+  // flag is cleared — a stale danger marker is how a real one stops being read.
+  const del = document.querySelector('#vv-ms-card input[data-flag="--delete"]');
+  const dry = document.getElementById('vv-ms-dryrun');
+  const warn = document.getElementById('vv-ms-delete-warn');
+  if (warn) {
+    const armed = del && del.checked && !(dry && dry.checked);
+    warn.style.display = armed ? '' : 'none';
+    if (armed) {
+      warn.textContent = 'deletes anything at ' + (rpath || 'the destination')
+                       + ' that is not in ' + (local || 'the source');
+    }
+  }
 }
 
 function _vvMsRenderDirs(dirsElId, dirs, parent, navFn) {
@@ -1815,7 +1855,7 @@ function vvMsBrowseLocal() {
     });
 }
 
-function vvMsRun() {
+async function vvMsRun() {
   const local  = document.getElementById('vv-ms-local').value.trim();
   const slot   = document.getElementById('vv-ms-host').value;
   const rpath  = document.getElementById('vv-ms-rpath').value.trim();
@@ -1831,6 +1871,24 @@ function vvMsRun() {
   if (!slot)   { vvAlert('Select a remote server.'); return; }
   if (!rpath)  { vvAlert('Enter a remote destination path.'); return; }
 
+  // The only confirm on this card, and only for the one flag that destroys data at the far end.
+  // Guarding every run would train the reflex that dismisses this one — a prompt that appears on
+  // every safe action is not read by the time an unsafe one arrives.
+  //
+  // Skipped under --dry-run, because that is exactly the rehearsal this is asking for, and
+  // refusing to let someone rehearse the dangerous case cheaply is the wrong lesson to teach.
+  if (flags.includes('--delete') && !isDry) {
+    const ok = await vvConfirm(
+      'This deletes anything in ' + rpath + ' on ' + slot + ' that is not in ' + local + '.\n\n'
+      + (local.endsWith('/')
+          ? 'The source ends in "/", so its CONTENTS are compared against the destination.'
+          : 'The source has no trailing "/", so the FOLDER ITSELF is copied into the destination — '
+          + 'a common cause of deleting the wrong level.')
+      + '\n\nRun a --dry-run first if you have not.',
+      { title: 'Run with --delete?', confirmText: 'Run it', type: 'warning' });
+    if (!ok) return;
+  }
+
   const btn    = document.getElementById('vv-ms-run-btn');
   const stat   = document.getElementById('vv-ms-run-status');
   const out    = document.getElementById('vv-ms-out');