feat(ui): add model thinking selector

packages/ui/src/lib/hooks/use-app-lifecycle.ts

@@ -69,6 +69,11 @@ export function useAppLifecycle(options: UseAppLifecycleOptions) {
         if (!instance) return
         emitSessionSidebarRequest({ instanceId: instance.id, action: "focus-agent-selector" })
       },
+      () => {
+        const instance = options.getActiveInstance()
+        if (!instance) return
+        emitSessionSidebarRequest({ instanceId: instance.id, action: "focus-variant-selector" })
+      },
     )
 
     registerEscapeShortcut(

packages/ui/src/lib/hooks/use-commands.ts

@@ -374,6 +374,20 @@ export function useCommands(options: UseCommandsOptions) {
       },
     })
 
+    commandRegistry.register({
+      id: "open-variant-selector",
+      label: "Select Model Variant",
+      description: "Choose a thinking effort for the current model",
+      category: "Agent & Model",
+      keywords: ["variant", "thinking", "reasoning", "effort"],
+      shortcut: { key: "T", meta: true, shift: true },
+      action: () => {
+        const instance = activeInstance()
+        if (!instance) return
+        emitSessionSidebarRequest({ instanceId: instance.id, action: "focus-variant-selector" })
+      },
+    })
+
     commandRegistry.register({
       id: "open-agent-selector",
       label: "Open Agent Selector",