Fix formula pages mobile responsiveness; fix missing mobile tabs

- Custom Formulas and Timeclock tabs were completely missing from the mobile
  dropdown selector, making them unreachable on phones; also adds AI Profile
  and Online Payments which were similarly absent
- Formula library header: flex-column on mobile so title and button stack
  cleanly instead of colliding
- Filter bar: icon-only button gets a visible label on mobile; added col-12
  so it renders full-width correctly at xs
- Import modal: add modal-dialog-scrollable so body scrolls on small screens;
  wrap field table in table-responsive to prevent horizontal overflow
- Settings card header: flex-column on mobile + flex-wrap on button group
  so the three buttons don't overflow off the right edge

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/wwwroot/js/formula-library.js

@@ -74,10 +74,12 @@
                     ${diagramHtml}
                     ${fields.length > 0 ? `
                     <h6 class="small fw-semibold mb-2">Input Fields (${fields.length})</h6>
+                    <div class="table-responsive">
                     <table class="table table-sm table-bordered">
                         <thead><tr><th>Field</th><th>Unit</th><th>Default</th></tr></thead>
                         <tbody>${fieldRows}</tbody>
-                    </table>` : '<p class="text-muted small">No fields defined.</p>'}
+                    </table>
+                    </div>` : '<p class="text-muted small">No fields defined.</p>'}
                     <div class="mt-2">
                         <h6 class="small fw-semibold mb-1">Formula Expression</h6>
                         <code class="d-block bg-light border rounded p-2 small text-break">${escHtml(d.formula)}</code>