fix: isolate InteractiveDemo story state from other stories

The InteractiveDemo play test was failing because it shared persisted
state with other stories (via the shared 'storybook-demo' workspaceId).
When DifferentModels runs first and sets thinking to 'medium' for Opus 4.5,
the InteractiveDemo story inherits that state.

Fix by giving InteractiveDemo its own unique workspaceId to ensure
test isolation.

Change-Id: I31bc0c6a2fc21a9a0084b966ce047422ce91339d
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

src/browser/components/ThinkingSlider.stories.tsx

@@ -75,6 +75,14 @@ export const DifferentModels: Story = {
 };
 
 export const InteractiveDemo: Story = {
+  // Use unique workspaceId to isolate state from other stories
+  decorators: [
+    (Story) => (
+      <ThinkingProvider workspaceId="storybook-interactive-demo">
+        <Story />
+      </ThinkingProvider>
+    ),
+  ],
   render: () => (
     <div className="bg-dark flex min-w-80 flex-col gap-[30px] p-10">
       <div className="text-bright font-primary mb-2.5 text-[13px]">