Port templates to NodeBB 4.14 benchpress escaping (#19)

NodeBB 4.14 turned on real HTML escaping for single-brace template interpolations (4.13 used an identity escape). This ports raw-HTML output to the double-brace forms ({{helper(...)}}, {{txEscape(content)}}, {{tx(name)}}), mirroring the harmony 2.2.72 -> 3.0.15 and core 4.13.2 -> 4.14.0 template diffs. Fixes the escaped-markup breakage on westgate.pw after the 2026.07.11-1 deploy.

Verified on a fresh 4.14.0 dev stack: no escaped tags on /, /categories, /category/2, /topic/1, /search; contract tests pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
Reviewed-on: #19
Reviewed-by: xtul <mpiasecki720@protonmail.com>
Co-authored-by: gitea-bot <gitea-bot@noreply.git.westgate.pw>
Co-committed-by: gitea-bot <gitea-bot@noreply.git.westgate.pw>

templates/partials/categories/children.tpl

@@ -3,7 +3,7 @@
 	{{{ if !./isSection }}}
 	<li data-cid="{./cid}" class="category-children-item small {./class}">
 		<div class="westgate-category-child d-flex gap-1">
-			{buildCategoryIcon(@value, "18px", "westgate-child-icon rounded-1")}
+			{{buildCategoryIcon(@value, "18px", "westgate-child-icon rounded-1")}}
 			<a href="{{{ if ./link }}}{./link}{{{ else }}}{config.relative_path}/category/{./slug}{{{ end }}}" class="text-reset fw-semibold flex-1">{./name}</a>
 		</div>
 	</li>