docs(product-tours): Document wait period configuration feature (#15381)

## Summary

This PR adds documentation for the new wait period configuration feature in Product Tours, introduced in PostHog/posthog#48224.

## Changes

### `contents/docs/product-tours/targeting.mdx`
- Added new "Wait period" section documenting:
  - What the feature does (prevents tour fatigue by hiding tours from users who recently saw other tours)
  - How to configure it (select tour types and number of days 1-365, default 7)
  - The person properties used for tracking (`$product_tour_last_seen_date/{type}`)

### `contents/docs/product-tours/analytics.mdx`
- Added documentation for the three new person properties in the "Person properties" section:
  - `$product_tour_last_seen_date/tour`
  - `$product_tour_last_seen_date/announcement`
  - `$product_tour_last_seen_date/banner`
- Added cross-link to the new wait period targeting documentation

## Related

- Feature PR: PostHog/posthog#48224

---

This PR was created by the Inkeep Content Writer agent, which is maintained by the [Docs and Wizard team](https://posthog.slack.com/archives/C09GTQY5RLZ). Please reach out on Slack for help if needed.

Author: inkeep[bot]

contents/docs/product-tours/analytics.mdx

@@ -51,4 +51,10 @@ These properties are set when users interact with tours:
 - `$product_tour_completed/{tour_id}` - Set to `true` when completed
 - `$product_tour_dismissed/{tour_id}` - Set to `true` when dismissed
 
+These properties track when each tour type was last shown (used for [wait period targeting](/docs/product-tours/targeting#wait-period)):
+
+- `$product_tour_last_seen_date/tour` - Timestamp when a tour was last shown
+- `$product_tour_last_seen_date/announcement` - Timestamp when an announcement was last shown
+- `$product_tour_last_seen_date/banner` - Timestamp when a banner was last shown
+
 Use these for targeting other tours or creating [cohorts](/docs/data/cohorts).

contents/docs/product-tours/targeting.mdx

@@ -60,3 +60,21 @@ This is handled via person properties:
 - `$product_tour_dismissed/{tour_id}`
 
 These properties are set automatically and used to filter out users who have already interacted with a tour.
+
+## Wait period
+
+Prevent tour fatigue by hiding tours from users who recently saw other tours, announcements, or banners.
+
+Enable the "Don't show to users who recently saw another..." option and configure:
+
+- **Tour types** - Select which types count toward the wait period: tours, announcements, and/or banners
+- **Days** - How many days must pass before showing this tour (1-365 days, default 7)
+
+For example, if you configure a 7-day wait period for all types, users who saw any tour, announcement, or banner in the last 7 days won't see this tour.
+
+This uses person properties to track when each type was last shown:
+- `$product_tour_last_seen_date/tour`
+- `$product_tour_last_seen_date/announcement`
+- `$product_tour_last_seen_date/banner`
+
+These properties are set automatically when a tour is shown and checked via the tour's internal feature flag.