Drop the every-main-post book icon from search/profile post lists (#15)

Implements Fix 4 of the wiki-links-and-search-followup spec (plugin repo). Removes the {{{ if ./isMainPost }}} fa-book fallback branch from templates/partials/posts_list_item.tpl — it put a book icon on every global-search result title. Only the isWikiArticle badge remains.

Deliberate blast radius: the partial also serves the seven account/profile post lists, which lose the marker too (restores pre-PR-#14 appearance). search-results.tpl untouched; its badge lights up once the companion plugin PR (fix/wiki-links-search-followup) delivers the flags.

Contract test extended to pin the removal; passing.

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

Reviewed-on: #15
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
Co-committed-by: vickydotbat <vickydotbat@tutamail.com>

tests/wiki-search-badge-contract.test.js

@@ -39,4 +39,10 @@ assertIncludes(read('scss/westgate/_search.scss'), '.westgate-wiki-badge', 'sear
 const languageKeys = JSON.parse(read('languages/en-GB/westgate.json'));
 assert(languageKeys['wiki-badge'], 'westgate language file should define the wiki-badge label');
 
+const postsListItem = read('templates/partials/posts_list_item.tpl');
+assert(
+	!postsListItem.includes('./isMainPost }}}<i class="fa fa-book'),
+	'posts_list_item.tpl should not render a book icon for plain main posts'
+);
+
 console.log('wiki search badge contract tests passed');