Port templates to NodeBB 4.14 benchpress escaping

NodeBB 4.14 registers a real __escape for template rendering (4.13 used
identity), so raw-HTML output must use the double-brace forms:
- HTML helpers: {{buildAvatar(...)}}, {{buildCategoryIcon(...)}}, etc.
- Pre-rendered HTML fields: {{txEscape(content)}} / {{./descriptionParsed}}
- Token-bearing text (nav labels, category names): {{tx(...)}}
- emails/partials/post-queue-body.tpl also adopts the 4.14 data shape
  (notification.category/topic/user/content).

Mirrors the harmony 2.2.72 -> 3.0.15 and core 4.13.2 -> 4.14.0 diffs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

templates/partials/posts_list_item.tpl

@@ -7,18 +7,18 @@
     <div class="post-body d-flex flex-column gap-1 mb-2">
         <div class="d-flex gap-2 post-info text-sm align-items-center">
             <div class="post-author d-flex align-items-center gap-1">
-                <a class="lh-1 text-decoration-none" href="{config.relative_path}/user/{./user.userslug}">{buildAvatar(./user, "16px", true, "not-responsive")}</a>
+                <a class="lh-1 text-decoration-none" href="{config.relative_path}/user/{./user.userslug}">{{buildAvatar(./user, "16px", true, "not-responsive")}}</a>
                 <a class="lh-1 fw-semibold" href="{config.relative_path}/user/{./user.userslug}">{../user.displayname}</a>
             </div>
             <span class="timeago text-muted lh-1" title="{./timestampISO}"></span>
         </div>
 
         <div component="post/content" class="content text-sm text-break">
-            {./content}
+            {{{ if ./txContent }}}{{tx(./content)}}{{{ else }}}{{txEscape(./content)}}{{{ end }}}
         </div>
     </div>
     <div class="mb-3 d-flex flex-wrap gap-1 w-100">
-        {buildCategoryLabel(./category, "a", "border")}
+        {{buildCategoryLabel(./category, "a", "border")}}
         <span data-tid="{./topic.tid}" component="topic/tags" class="lh-1 tag-list d-flex flex-wrap gap-1 {{{ if !./topic.tags.length }}}hidden{{{ end }}}">
             {{{ each ./topic.tags }}}
             <a href="{config.relative_path}/tags/{./valueEncoded}"><span class="badge border border-gray-300 fw-normal tag tag-class-{./class}" data-tag="{./value}">{./valueEscaped}</span></a>