feat(research): persist popularity metrics

[hubab1]

Summary

• add an app-independent Apple Ads popularity workflow for pre-live research-project keywords
• persist popularity on canonical shared queries without creating fake tracked apps, keyword tracks, or refresh statuses
• revalidate project/keyword incarnations and exact query scalars after provider suspension before one atomic write
• reuse the sequential Apple Ads client with 100 terms per request, a 500-keyword workflow cap, storefront grouping, a seven-day cache policy, and structured partial outcomes
• wire the optional workflow through AppServices using the current context app and exact web-session reconnect state

Correctness and safety

• provider fetch and SwiftData persistence are split so the workflow owns rollback and commit
• all post-provider paths revalidate generations and read the transaction-current cache
• concurrent newer popularity wins; difficulty-only rows do not suppress the first real popularity result
• missing context/session, reconnect-required, expiry, unsupported storefront, rate limiting, provider failures, cancellation, configuration changes, and not-found results have explicit outcomes
• provider messages and web-session secrets are not exposed in outcomes
• existing tracked apps, tracks, and refresh statuses remain unchanged

This progresses #3 but does not close it.

Validation

• focused popularity, Apple Ads, dependency-wiring, and ranking regression suites passed
• full OpenASO suite passed: 541 tests (545 parameterized test invocations)
• project-file lint and whitespace checks passed

Known schema boundary

KeywordDailyMetric has no Apple Ads context dimension and only one legacy row timestamp. Persisted cache outcomes therefore report context as unknown, while the requested context is exposed only for evidence fetched by the current invocation.