Sentry: release health by session, and an honest project-stats fix

The Sentry integration now includes two read-only tools for Release Health. Session counts can be grouped by release, with adoption in the selected time window, and a single release can be opened for its metadata and session share. They use the same Sentry auth token you already configure; no new credentials or integration slug.

sentry_sessions_by_release reads organization session stats grouped by release. sentry_release_detail returns metadata and session share for one version in that window. A longer window, such as 24 hours, still includes sessions from older releases on the project. A short window shows how much recent traffic is already on the new release. Both use Sentry session stats, not issue search.

sentry_projects_stats now reports project event volume. It is not a release-adoption chart. The full Opsphere operational catalog reaches 353 tools. This is a capability expansion on the existing Sentry integration, not a new vendor logo on the hub.