GraphReFly Graph container — sugar layer over graphrefly_core::Core with named namespace, mount/unmount composition, describe() JSON introspection, and observe() sink-style message tap.

Status (M2 Slice E+ — 2026-05-05)

Read-side introspection + composition slice. Lands the canonical-spec Graph surface for state / derived / dynamic named sugar (§3.9), add / node / name_of / try_resolve namespace (§3.5), mount / mount_new / mount_with / unmount / ancestors composition (§3.4), destroy / signal_invalidate lifecycle (§3.7), describe() JSON form (§3.6 + Appendix B), and observe() / observe_all() default sink-style tap (§3.6.2).

Hard-breaks the M2 starter (Slice D) sugar API: state(name, initial) replaces state(initial), etc. Pre-1.0 — no compat shims (per feedback_no_backward_compat.md).

Out of scope (subsequent slices):

• Reactive describe() / observe() — Node<GraphDescribeOutput> and Node<ObserveChangeset> modes (§3.6.1 / §3.6.2 reactive variants). Need a Core-level topology-change notification primitive.
• Async-iterable observe() modes — structured / timeline / causal / derived opts.
• describe() non-JSON formats — pretty / mermaid / d2 / stage-log.
• describe({ explain }) / describe({ reachable }) — causal chain + reachability walks.
• Snapshot / restore + content addressing — V1 lazy CID / V2 schema validation / V3 caps + cross-graph refs (§3.8 + Phase 6).
• mutate() factory — DS-14 RAII + audit append substrate.
• Cross-Core (multi-binding) mount — open question 1 in archive/docs/SESSION-rust-port-architecture.md Part 6; post-M6.
• Meta annotations + versioning fields in describe output — need metadata-storage primitive on Core.

Crate lints

#![forbid(unsafe_code)] per workspace policy.