feat(metadata): add refresh progress UI

[hubab1]

Summary

• add one app-wide metadata refresh progress state machine with persistent terminal results
• expose refresh actions in the sidebar and keyword ranking results, with per-storefront and per-provider details
• support cautious cancellation, retry, dismiss, partial-failure reporting, and background-store refresh notifications
• invalidate icons and screenshot rows by metadata revision while preventing stale asynchronous image publication and bounding thumbnail cache memory

Validation

• AppMetadataRefreshProgressStoreTests: 12 passed
• full OpenASO suite: 270 passed, 0 failed
• signed Debug build succeeded and the built app launched successfully
• independent P1/P2 code and UX reviews passed

Manual review gate

This remains a draft because it is user-visible metadata refresh UX stacked on #31. Please exercise default plus tracked storefront refresh, partial/offline provider failures, cancellation during an active storefront, retry/dismiss, sidebar and ranking-list presentation, and icon/screenshot refresh behavior before merge.

Related to #2.