feat: sessions page workspace-first flow + workspace instance chips

- Sessions page: replaced CreateSessionForm with workspace selector + ToolStarter
  - Fetches workspaces, shows dropdown, then renders ToolStarter for selected workspace
  - Removed old project/repo/tool-type/config-profile/clone-mode flow
- Workspace cards: new WorkspaceInstanceChips component fetches and displays
  running instances per workspace with status-colored chips and open links
- Styles: .instance-chip variants (running/starting/error), .tool-starter-header

Quality gates: tsc --noEmit clean, pytest workspaces API (9 passed, 1 skipped)

apps/web/src/styles.css

@@ -5551,3 +5551,67 @@ a:active,
 	gap: var(--space-2);
 	font-size: var(--font-size-sm);
 }
+
+/* ─── Instance Chips ─── */
+.instance-chips {
+	display: flex;
+	flex-wrap: wrap;
+	gap: var(--space-2);
+	margin-top: var(--space-2);
+}
+
+.instance-chip {
+	display: inline-flex;
+	align-items: center;
+	gap: var(--space-1);
+	padding: 0.2rem 0.5rem;
+	border-radius: 999px;
+	font-size: var(--font-size-sm);
+	background: var(--bg);
+	border: 1px solid var(--border);
+}
+
+.instance-chip.running {
+	background: var(--success-light);
+	border-color: var(--success);
+	color: var(--success);
+}
+
+.instance-chip.starting,
+.instance-chip.building,
+.instance-chip.probing {
+	background: var(--warning-light);
+	border-color: var(--warning);
+	color: var(--warning);
+}
+
+.instance-chip.error,
+.instance-chip.unhealthy,
+.instance-chip.stopped {
+	background: var(--danger-light);
+	border-color: var(--danger);
+	color: var(--danger);
+}
+
+.instance-chip a {
+	font-size: 0.75rem;
+	opacity: 0.7;
+}
+
+.instance-chip a:hover {
+	opacity: 1;
+}
+
+/* ─── Tool Starter Header ─── */
+.tool-starter-header {
+	display: flex;
+	justify-content: space-between;
+	align-items: center;
+	margin-bottom: var(--space-3);
+	padding-bottom: var(--space-2);
+	border-bottom: 1px solid var(--border);
+}
+
+.tool-starter-header h4 {
+	margin: 0;
+}