Add skeleton loading states across all tracking pages

- Replace CircularProgress spinners with content-aware skeleton screens
- Add FormSkeleton for form loading states (feeding, sleep, diaper pages)
- Add ActivityListSkeleton for recent activities loading
- Improves perceived performance with layout-matching placeholders

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

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

maternal-web/app/page.tsx

@@ -8,6 +8,7 @@ import { EmailVerificationBanner } from '@/components/common/EmailVerificationBa
 import { ErrorBoundary } from '@/components/common/ErrorBoundary';
 import { DataErrorFallback } from '@/components/common/ErrorFallbacks';
 import { NetworkStatusIndicator } from '@/components/common/NetworkStatusIndicator';
+import { StatGridSkeleton } from '@/components/common/LoadingSkeletons';
 import {
   Restaurant,
   Hotel,
@@ -147,12 +148,11 @@ export default function HomePage() {
             isolate
             fallback={<DataErrorFallback error={new Error('Failed to load summary')} />}
           >
-            <Paper sx={{ p: 3 }}>
-              {loading ? (
-                <Box sx={{ display: 'flex', justifyContent: 'center', py: 4 }}>
-                  <CircularProgress />
-                </Box>
-              ) : !dailySummary ? (
+            {loading ? (
+              <StatGridSkeleton count={3} />
+            ) : (
+              <Paper sx={{ p: 3 }}>
+                {!dailySummary ? (
                 <Box sx={{ textAlign: 'center', py: 4 }}>
                   <Typography variant="body2" color="text.secondary">
                     {children.length === 0
@@ -198,8 +198,9 @@ export default function HomePage() {
                     </Box>
                   </Grid>
                 </Grid>
-              )}
-            </Paper>
+                )}
+              </Paper>
+            )}
           </ErrorBoundary>
 
           {/* Next Predicted Activity */}