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/styles.css

@@ -5454,3 +5454,52 @@ a:active,
 .workspace-chip .ws-actions button.danger-text:hover {
 	color: var(--danger);
 }
+
+/* ─── Workspace Create Inline ─── */
+
+.workspace-create-inline {
+	padding: var(--space-5);
+	margin-bottom: var(--space-5);
+}
+
+.workspace-create-inline h3 {
+	margin: 0 0 var(--space-4) 0;
+	display: flex;
+	align-items: center;
+	gap: var(--space-2);
+}
+
+.workspace-create-form-grid {
+	display: grid;
+	grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+	gap: var(--space-4);
+	align-items: end;
+}
+
+.workspace-create-form-grid .form-group {
+	display: flex;
+	flex-direction: column;
+	gap: var(--space-1);
+}
+
+.workspace-create-form-grid label {
+	font-size: var(--font-size-sm);
+	color: var(--muted);
+}
+
+.workspace-create-form-grid input,
+.workspace-create-form-grid select {
+	padding: var(--space-2) var(--space-3);
+	border: 1px solid var(--border);
+	border-radius: 8px;
+	font: inherit;
+	background: var(--panel);
+	color: var(--ink);
+}
+
+.workspace-create-form-grid .form-actions {
+	display: flex;
+	gap: var(--space-3);
+	justify-content: flex-end;
+	margin-top: var(--space-2);
+}