<ul><li>Performed full CRUD QA audit on Solutions Manager admin module (page=2010) — tested all 12 operations across 3 tabs: Categories, Features/Sections, Solutions Items. All 12 model-layer and 10 HTTP endpoint tests passed (200/201).</li><li>BUG FIX: <code>controller/solution/SolutionController.php</code> — <code>addSolutionCategory()</code> line 567 and <code>updateSolutionCategory()</code> line 635: Direct access to <code>$_FILES['solution_category_sharecard']</code> without <code>isset()</code> guard caused PHP Warning <em>Undefined array key</em> on every category add/edit when no image is uploaded. Fixed with <code>isset()</code> check.</li><li>BUG FIX: <code>classes/user/User.class.php</code> — <code>getOS()</code> line 930 and <code>getUserBrowser()</code> line 968: <code>$_SERVER['HTTP_USER_AGENT']</code> accessed without null coalescing operator, causing PHP Warning when called from CLI (curl/API login). Fixed with <code>?? ''</code>.</li><li>BUG FIX: <code>controller/auth/auth.controller.php</code> — <code>prepareLoginData()</code> line 742 and <code>ipdata</code> array line 813: Same <code>HTTP_USER_AGENT</code> missing key warning during AJAX login. Fixed with <code>?? ''</code>.</li><li>All 4 PHP warnings now eliminated from login and category CRUD flows — verified clean responses with no PHP errors.</li></ul>