docs(product tours): Update docs for draft auto-save system (#15192)

## Changes

Updates product tours documentation to reflect the new draft auto-save system introduced in [PostHog/posthog#48393](PostHog/posthog#48393).

### What changed in the product

Product tours now use a draft system when editing:
- Changes auto-save as you edit with status indicators (unsaved/saving/saved)
- Click **Save** to publish changes or **Cancel** to discard the draft
- If you close your browser with unpublished changes, a banner appears with options to continue editing or discard
- The toolbar and main app stay in sync automatically

### Files updated

- **`contents/docs/product-tours/creating-product-tours.mdx`** – Updated the "Save and launch" section to describe auto-save behavior and the publish/discard workflow.
- **`contents/docs/product-tours/managing-tours.mdx`** – Updated the "Editing live tours" section to clarify that changes save to a draft first (not published immediately) and document the unsaved changes banner.

Author: inkeep[bot]

contents/docs/product-tours/creating-product-tours.mdx

@@ -94,4 +94,6 @@ Embed a survey question mid-tour (open text or rating scale). Responses are capt
 
 ## Save and launch
 
-Click **Save** in the toolbar to save your tour as a draft. When ready, [launch the tour](/docs/product-tours/managing-tours).
+Changes auto-save as you edit. A status indicator in the header shows whether your changes are **unsaved**, **saving**, or **saved**.
+
+When you're done, click **Save** to publish your changes or **Cancel** to discard the draft. When ready, [launch the tour](/docs/product-tours/managing-tours).

contents/docs/product-tours/managing-tours.mdx

@@ -27,7 +27,11 @@ To stop a running tour, click **Stop**. The tour stops showing immediately.
 
 ## Editing live tours
 
-You can edit a running tour. Changes take effect immediately:
+You can edit a running tour. Changes auto-save to a draft as you work – they aren't published until you click **Save**. Click **Cancel** to discard your draft.
+
+If you close your browser with unpublished changes, a banner appears on the tour view page with options to **Continue editing** or **Discard** the draft.
+
+You can edit:
 
 - Content changes (text, images, buttons)
 - Targeting changes (URL, user filters)