docs(changelog): add setPrice and setPrices affordances details

Author: hanrw

CHANGELOG.md

@@ -18,6 +18,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Multi-territory subscription `setPrices` (batch)** — `asc subscriptions prices set-batch --subscription-id <id> --price USA=spp-1 --price JPN=spp-2 ...`. Mirrors iOS `setPrices(prices:)`. Returns the post-write schedule.
 - **Subscription promotional images** — `asc subscription-images list|upload|delete` and `GET /api/v1/subscriptions/:id/images`. New `SubscriptionPromotionalImage` domain type with `delete` suppression while `state.isPendingReview` (mirrors IAP images).
 - **`asc subscriptions update --period <PERIOD>`** — change billing period (ONE_WEEK, ONE_MONTH, …, ONE_YEAR) on an existing subscription. Mirrors the iOS app's `subscription.update(subscriptionPeriod:)`.
+- **`setPrice` affordance + `POST /api/v1/iap/{id}/prices/set`** — IAPs now advertise how to set or change their base price/territory. Calling with a new `baseTerritory` is how the iOS app implements "Change Base Territory" — ASC replaces the schedule and re-equalizes other territories.
+- **`setPrices` affordance + `POST /api/v1/subscriptions/{id}/prices/set-batch`** — subscriptions now advertise the batch multi-territory price-set operation. Body accepts `{ prices: [{territory, pricePointId, startDate?, preserveCurrentPrice?}] }` (preferred) or a flat `{ "USA": "spp-1", "JPN": "spp-2" }` shorthand.
 
 ### Fixed
 - **IAP/Subscription availability returned only ~10 territories instead of all ~175** — the parent endpoint's `include=availableTerritories` truncates the relationship to a single page. `getAvailability` now issues two parallel calls (attributes + dedicated `/availableTerritories?limit=200`) so the full territory list reaches the frontend's Availability tab. Matches the iOS SDK's `fetchAvailability` composition.