perf(comments): lazy-render top-level reply forms

The reply form used to render ~13 lines of hidden markup under every
top-level comment, so a 50-comment video shipped roughly 650 lines of
inert DOM to every signed-in viewer. Replaced with a single
<template id="ytc-reply-form-tpl"> plus a per-comment slot div; the
first click on Reply clones the template, wires the IDs
(replyForm{id}, replyBody{id}, data-parent-id, data-video-id) and
appends it, so toggle behavior stays identical from the user's side.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

resources/views/components/video-comments.blade.php

@@ -156,20 +156,12 @@
                         @endif
                     </div>
 
-                    {{-- Reply form --}}
+                    {{-- Reply form is lazy-cloned from #ytc-reply-form-tpl on
+                         first click; the ~13-line markup used to render for
+                         every top-level comment (so a 50-comment video shipped
+                         ~650 lines of hidden form markup to every viewer). --}}
                     @auth
-                    <div class="ytc-reply-form" id="replyForm{{ $comment->id }}">
+                    <div class="ytc-reply-slot" data-comment-id="{{ $comment->id }}" data-video-id="{{ $video->getRouteKey() }}"></div>
-                        <img src="{{ Auth::user()->avatar_url }}" class="ytc-avatar ytc-avatar-sm" alt="{{ Auth::user()->name }}">
-                        <div class="ytc-input-wrap">
-                            <textarea class="ytc-textarea ytc-reply-textarea" id="replyBody{{ $comment->id }}"
-                                      placeholder="Add a reply..." rows="1"></textarea>
-                            <div class="ytc-form-actions">
-                                <button class="ytc-btn ytc-btn-cancel _comment-cancel-reply-trigger" data-comment-id="{{ $comment->id }}">Cancel</button>
-                                <button class="ytc-btn ytc-btn-submit _comment-submit-reply-trigger"
-                                        data-video-id="{{ $video->getRouteKey() }}" data-parent-id="{{ $comment->id }}">Reply</button>
-                            </div>
-                        </div>
-                    </div>
                     @endauth
 
                     {{-- Replies --}}
@@ -1062,10 +1054,29 @@ async function toggleTranslate(btn) {
     }
 }
 
-// ── Reply form ────────────────────────────────────────
+// ── Reply form (lazy-rendered from a <template>) ──────
+// Replaces the per-comment inline markup that used to live in the DOM
+// pre-hidden. First click on "Reply" clones the template into the comment's
+// .ytc-reply-slot and wires its IDs. Subsequent toggles just show/hide.
 function toggleReplyForm(commentId) {
-    const form = document.getElementById('replyForm' + commentId);
+    let form = document.getElementById('replyForm' + commentId);
-    if (!form) return;
+    if (!form) {
+        const slot = document.querySelector('.ytc-reply-slot[data-comment-id="' + commentId + '"]');
+        const tpl  = document.getElementById('ytc-reply-form-tpl');
+        if (!slot || !tpl) return;
+        const frag = tpl.content.cloneNode(true);
+        const root = frag.querySelector('.ytc-reply-form');
+        const ta   = frag.querySelector('.ytc-reply-textarea');
+        const cancel = frag.querySelector('._comment-cancel-reply-trigger');
+        const submit = frag.querySelector('._comment-submit-reply-trigger');
+        root.id = 'replyForm' + commentId;
+        ta.id   = 'replyBody' + commentId;
+        cancel.dataset.commentId = commentId;
+        submit.dataset.parentId  = commentId;
+        submit.dataset.videoId   = slot.dataset.videoId || YTC.videoId;
+        slot.appendChild(frag);
+        form = root;
+    }
     const isOpen = form.classList.contains('open');
     document.querySelectorAll('.ytc-reply-form.open').forEach(f => f.classList.remove('open'));
     if (!isOpen) {
@@ -1513,3 +1524,22 @@ window._comment = {
 
 })();
 </script>
+
+@auth
+{{-- Reply-form template. Cloned into .ytc-reply-slot the first time a user
+     clicks Reply on a given comment. Keeping it here (not in the layout)
+     means the markup travels with the comments component — the only place
+     that uses it. --}}
+<template id="ytc-reply-form-tpl">
+    <div class="ytc-reply-form">
+        <img src="{{ Auth::user()->avatar_url }}" class="ytc-avatar ytc-avatar-sm" alt="{{ Auth::user()->name }}">
+        <div class="ytc-input-wrap">
+            <textarea class="ytc-textarea ytc-reply-textarea" placeholder="Add a reply..." rows="1"></textarea>
+            <div class="ytc-form-actions">
+                <button class="ytc-btn ytc-btn-cancel _comment-cancel-reply-trigger">Cancel</button>
+                <button class="ytc-btn ytc-btn-submit _comment-submit-reply-trigger">Reply</button>
+            </div>
+        </div>
+    </div>
+</template>
+@endauth