Backend Architecture Guardrails

These rules supplement the repository's root AGENTS.md.

Configuration ownership. config owns source configuration, drafts and persistence. The effects layer owns patch orchestration. Rollbackable transactions publish state after persistence and commit; already applied runtime and independently committed state remain authoritative even when a later step fails. Preserve that state, its notifications and the error.
Effect ownership. The declarative registry classifies every Verge patch field, including fields without effects and platform-specific fields. Effects reconcile toward the requested state with explicit dependencies and ordering. Configuration rollback does not imply reversal of OS or lifecycle effects.
Shared wire contract. Notifications are typed. Event names, status values and payload shapes stay compatible with frontend producers and consumers.
Synchronization ownership. Configuration-write serialization precedes configuration-update ownership, which precedes Core lifecycle ownership. When both are held, the lifecycle lock precedes the DNS lock. Independent transactions retain their ownership boundaries; asynchronous work does not hold synchronous data guards across suspension.
Retry ownership. Bounded retries share backend policy while preserving attempts, delays and terminal errors. Background monitors own their lifetime and cancellation separately; waiting for a condition or traversing distinct candidates is not a retry policy.