Core graph skeleton for Trellis.

This crate currently defines typed identities, graph metadata, scope metadata, declared dependencies, deterministic inspection, input transactions, pure derived node recomputation, collection diffs, and data-only resource plans with recursive scope teardown and materialized output frames. Transaction results include deterministic phase traces, and failures expose typed categories.

API stability

Trellis is pre-1.0. Core semantics are intended to be more stable than item names and exact signatures: resource plans are data, graph mutation is transactional, dependencies are explicit, scopes own lifecycle, outputs are revisioned, and incremental behavior must remain checkable against full recompute.