feat: add mobile support for Workspaces page with workspace creation

- WorkspacesPage.tsx: detect mobile viewport, show MobileListView / MobileDetailView / MobileFAB
- Mobile list: tap workspace to view details (branch, status, path, instances, sync time)
- Mobile detail: view workspace fields with Edit and Delete actions
- Mobile FAB: opens inline WorkspaceCreateForm
- New styles/pages/workspaces.css with responsive grid and card styles
- Import workspaces.css in main.tsx

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

apps/web/src/styles/pages/workspaces.css

@@ -0,0 +1,126 @@
+/** Workspaces page styles */
+
+/* Desktop */
+.workspaces-page {
+	padding: var(--space-4);
+}
+
+.workspaces-grid {
+	display: grid;
+	grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
+	gap: var(--space-4);
+	margin-top: var(--space-4);
+}
+
+/* Workspace card */
+.workspace-card {
+	padding: var(--space-4);
+	border: 1px solid var(--border);
+	border-radius: 12px;
+	background: var(--panel);
+	transition: box-shadow 0.15s ease;
+}
+
+.workspace-card:hover {
+	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
+}
+
+.workspace-card.loading {
+	opacity: 0.6;
+	pointer-events: none;
+}
+
+.workspace-header-link {
+	display: block;
+	text-decoration: none;
+	color: inherit;
+}
+
+.workspace-header {
+	display: flex;
+	align-items: center;
+	gap: var(--space-2);
+	margin-bottom: var(--space-2);
+}
+
+.workspace-header h4 {
+	margin: 0;
+	font-size: 1.1rem;
+	flex: 1;
+}
+
+.workspace-meta {
+	margin-bottom: var(--space-3);
+}
+
+.workspace-meta p {
+	margin: 0.15rem 0;
+	font-size: 0.875rem;
+	color: var(--muted);
+}
+
+.workspace-actions {
+	display: flex;
+	gap: var(--space-2);
+	flex-wrap: wrap;
+}
+
+/* Status badges */
+.status-badge {
+	font-size: 0.75rem;
+	font-weight: 600;
+	padding: 0.15rem 0.5rem;
+	border-radius: 999px;
+	text-transform: capitalize;
+}
+
+.status-ready {
+	background: var(--success-light);
+	color: var(--success);
+}
+
+.status-syncing {
+	background: var(--warning-light);
+	color: var(--warning);
+}
+
+.status-error {
+	background: var(--danger-light);
+	color: var(--danger);
+}
+
+/* Empty state */
+.empty-state {
+	text-align: center;
+	padding: var(--space-10) var(--space-4);
+	color: var(--muted);
+}
+
+.empty-state p {
+	margin-bottom: var(--space-4);
+}
+
+/* Mobile */
+@media (max-width: 767px) {
+	.workspaces-page {
+		padding: var(--space-2);
+	}
+
+	.workspaces-grid {
+		grid-template-columns: 1fr;
+		gap: var(--space-3);
+	}
+
+	.workspace-card {
+		padding: var(--space-3);
+	}
+
+	.workspace-actions {
+		flex-direction: column;
+	}
+
+	.workspace-actions .btn {
+		width: 100%;
+		justify-content: center;
+	}
+}