feat: add mobile support for Projects page with repository creation

- ProjectsPage.tsx: detect mobile viewport, show MobileListView / custom detail view / MobileFAB
- Mobile list: tap project to view details (name, description, repositories, workspaces)
- Mobile detail: shows repositories with New Workspace buttons, Add Repository button, Edit/Delete project actions
- Mobile FAB: opens inline project creation form
- RepositoryCreateDialog reused for mobile 'Add Repository' flow
- New CSS: .mobile-form-actions, .mobile-form-group for mobile form layouts

Quality gates: tsc --noEmit pass, npm run build pass, 80/80 tests pass

apps/web/src/styles/utilities.css

@@ -2100,6 +2100,33 @@ a.nav-item,
 	padding-bottom: calc(1.25rem + 64px);
 }
 
+/* Mobile form actions (bottom button row) */
+.mobile-form-actions {
+	display: flex;
+	flex-direction: column;
+	gap: var(--space-2);
+	padding: var(--space-3) var(--space-2);
+	margin-top: auto;
+}
+
+.mobile-form-actions .primary-button,
+.mobile-form-actions .secondary-button,
+.mobile-form-actions .ghost-button,
+.mobile-form-actions .danger-button {
+	width: 100%;
+	justify-content: center;
+	min-height: 48px;
+}
+
+/* Mobile form group (inline fields) */
+.mobile-form-group {
+	padding: var(--space-2);
+	background: var(--panel);
+	border-radius: 8px;
+	border: 1px solid var(--border);
+	margin-bottom: var(--space-2);
+}
+
 /* Ensure minimum touch targets on mobile */
 button,
 a,