Add Sentry feature gating (Phase 5) — breaks pattern in multi_region_ha

Pattern '4 commercial + 2 na + 1 partial + 1 oss' diverges from MongoDB
and CockroachDB convergent '5 commercial + 2 na + 1 partial' in exactly
ONE field: multi_region_ha=oss (vs commercial).

Justification: genuine semantic difference, not artifact. In databases,
multi_region_ha measures cluster cross-region survival goals (technically
gated). In observability, multi_region_ha measures data residency /
regional ingestion architecture, which Sentry has democratized:
EU Data Residency (Frankfurt) is offered to customers on all plan tiers
including free Developer at no extra cost (per docs.sentry.io and
sentry.zendesk.com explicit confirmation). Self-hosted FSL deployments
additionally have unrestricted multi-region freedom.

Atlas applies category-aware semantics rather than forcing database
interpretation. First emergent example of category-specific feature_gating
differentiation in the dataset.

Falsifiability test for next observability record (Grafana):
- if multi_region_ha=oss/partial: split solidifies as pattern
- if multi_region_ha=commercial: Sentry break is product-specific only

Cross-record N=3 robust patterns confirmed: 'compliance bundle'
(sso_saml + rbac_fine_grained + audit_logs + sla_support_tier all
commercial) is category-agnostic; advanced_analytics='partial' is
structural for analytics-rich open-core products.

Author: opencoreatlas