Rust Phase 4 compiled schematic graph contract

Status: accepted at 86247f2. This slice establishes the transport and identity authority before implementing the native schematic compiler. It does not change the accepted Python producer and does not add a WASM operation.

Contract boundary

compiled-schematic-graph-a0.tsp owns the complete a0 envelope and its ten row collections. TypeSpec generates strict JSON Schema, Rust, Python/msgspec, and TypeScript projections. Unknown record fields and unregistered enum values fail during transport decoding. Wire names such as type and the registered dotted source-identity selectors are preserved even when a target language requires a safe local name. The a0 shape is closed: every additive field, source selector, enum value, or row family requires a new schema version and an explicit migration.

Generated projections are structural DTOs. Graph-wide reference closure, UUIDv7 validity, uniqueness, topology, role-dependent fields, and identity replay remain semantic checks. Phase 4's native compiler step must port the accepted Python validator and may add handwritten Rust validation beside generated types; it must not hand-edit generated files.

Identity authority

compiled_schematic_graph_a0_vectors.json freezes project-scope normalization plus source-derived and topology-derived UUIDv7 results. The current Python allocator replays those values. The vectors cover every row type, both source and derived branches, UUIDv7 version/variant bits, selector precedence, normalization, and fail-closed inputs. The native allocator must consume the same vector file before it may emit a compiled graph. This keeps identity behavior language neutral without prematurely moving compiler logic into the transport generator.

Evidence and ownership

• Rack L0_049 checks Python and TypeScript regeneration and use.
• Rack L0_050 decodes all ten row families and replays identity vectors.
• The Rust contracts crate uses a package-owned strict envelope and row-literal decoder over the generated DTO.
• Rack L3_018 decodes all four reference-project producer outputs through the generated contract.
• TypeSpec remains the only editable transport source of truth.
• WASM packaging remains deferred under the native-first ADR.

Next gate

Promotion of this contract authorizes the native validator, deterministic allocator, named multi-file source bundle, and schematic compiler. Compiler promotion requires Python differential evidence on generated and corpus schematics; merely decoding this structural fixture is not compiler parity.