feat(manacore/web): add responsive mobile styles for PWA readiness

Navigation:
- PillNavigation: icon-only pills on mobile (<640px), 44px min touch targets
- QuickInputBar: tighter padding and smaller height on mobile
- Main content area: reduced padding on small screens (px-3 py-4)

Typography & Global:
- Responsive heading sizes (h1-h3 scale down on mobile)
- Safe-area body padding for PWA standalone mode

Module ListViews:
- Todo: 44px min-height task items, larger checkboxes on mobile
- Calendar: 44px min-height event cards, larger quick-add input
- Contacts: 44px min-height contact items
- Chat: min-h-[44px] conversation items, tighter container padding

Layout:
- SplitPaneLayout: stacks vertically on mobile (<768px), hides resize handle

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-ui/src/quick-input/InputBar.svelte

@@ -586,6 +586,20 @@
 		z-index: auto;
 	}
 
+	/* Mobile: tighter padding, full-width input */
+	@media (max-width: 640px) {
+		.quick-input-bar {
+			padding: 0.5rem 0.5rem;
+			height: 64px;
+		}
+
+		.input-container {
+			padding: 0.5rem 1rem;
+			height: 48px;
+			gap: 0.5rem;
+		}
+	}
+
 	/* Leave space for FAB on mobile */
 	@media (max-width: 900px) {
 		.quick-input-bar.has-fab-right {