Change employment overlaps to informational only

- Rename "Employment Overlap" to "Concurrent Employment"
- Remove score penalty for overlaps (often legitimate: part-time, consulting, transitions)
- Change severity from Warning/Critical to Info
- Update scoring explanation to note overlaps are not penalised

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/TrueCV.Web/Components/Pages/Report.razor

@@ -200,7 +200,7 @@
                                 <li>Director claims not verified: <strong>-20 pts</strong> each</li>
                                 <li>Employment before company existed: <strong>-20 pts</strong></li>
                                 <li>Employment gaps: <strong>-1 to -10 pts</strong> per gap</li>
-                                <li>Excessive overlaps: <strong>-2 pts</strong> per month</li>
+                                <li>Concurrent employment is noted but not penalised</li>
                             </ul>
                         </div>
                     </div>