fix: allow workspace creation from workspaces page

- Replace awkward first-workspace-guessing logic with inline project/repo selector
- New WorkspaceCreateInline component with cascading dropdowns:
  - Select project → loads repositories for that project
  - Select repository → enter workspace name + branch
  - Submit creates workspace via top-level POST /workspaces/
- Add createWorkspaceTopLevel() API client for flat endpoint
- Works even with zero existing workspaces (shows create button in empty state)
- Add CSS grid layout for inline create form
- TypeScript + eslint clean

apps/web/src/pages/workspace-detail.tsx

@@ -100,7 +100,10 @@ function TabBar({
 					role="tab"
 					aria-selected={active === tab.id}
 				>
-					<Icon name={tab.icon as "folder" | "branch" | "terminal" | "settings"} size="sm" />
+					<Icon
+						name={tab.icon as "folder" | "branch" | "terminal" | "settings"}
+						size="sm"
+					/>
 					{tab.label}
 				</button>
 			))}
@@ -132,7 +135,9 @@ function MobileTabBar({
 					role="tab"
 					aria-selected={active === tab.id}
 				>
-					<Icon name={tab.icon as "folder" | "branch" | "terminal" | "settings"} />
+					<Icon
+						name={tab.icon as "folder" | "branch" | "terminal" | "settings"}
+					/>
 					<span>{tab.label}</span>
 				</button>
 			))}