Show "Goal exceeded" instead of negative remaining minutes

When weekly intensity exceeds the phase goal, display "Goal exceeded by X min"
instead of the confusing "Remaining: -X min".

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

src/components/dashboard/data-panel.test.tsx

@@ -142,10 +142,10 @@ describe("DataPanel", () => {
       expect(screen.getByText(/Remaining: 0 min/)).toBeInTheDocument();
     });
 
-    it("displays negative remaining minutes", () => {
+    it("displays goal exceeded message for negative remaining minutes", () => {
       render(<DataPanel {...baseProps} remainingMinutes={-50} />);
 
-      expect(screen.getByText(/Remaining: -50 min/)).toBeInTheDocument();
+      expect(screen.getByText(/Goal exceeded by 50 min/)).toBeInTheDocument();
     });
   });
 

src/components/dashboard/data-panel.tsx

@@ -76,7 +76,11 @@ export function DataPanel({
             />
           </div>
         </li>
-        <li>Remaining: {remainingMinutes} min</li>
+        <li>
+          {remainingMinutes >= 0
+            ? `Remaining: ${remainingMinutes} min`
+            : `Goal exceeded by ${Math.abs(remainingMinutes)} min`}
+        </li>
       </ul>
     </div>
   );