Evaluate flatc/FlatBuffers-driven codegen vs hand-rolled schema/type conformance oracles

[MGudgin]

Description of the task

Evaluate whether a schema-driven codegen pipeline — for example an internal FlatBuffers schema compiled with flatc — could replace the hand-rolled conformance oracles that keep the JSON schema, the generated Rust wire model, and the generated TypeScript wire types in agreement.
Today these artifacts are kept in sync by bespoke generators (mxc_schema_gen, wxc_common::ts_emit) plus hand-written conformance helpers and tests (sdk/tests/unit/conformance-helpers.ts, wire-conformance*.test.ts). @bbonaby raised in review of #580 that a single FlatBuffer schema could instead drive flatc-generated JSON schema, Rust types, and TypeScript types, with the FlatBuffer SDK verifying JSON — potentially reducing the amount of bespoke code we author and maintain.
The current no-third-party-generator approach is deliberate. The outcome of this task is a recommendation weighing that trade-off (maintenance cost and comprehensibility of the hand-rolled oracles vs. adopting an external generator/toolchain), not a commitment to switch.

Additional context

• Non-blocking design discussion from the review of Phase 3a: decouple ProcessContainer backend selection from schema version #580.
• Pre-existing surface, introduced in Phase 2.5 (SDK wire-type conformance).

[github-actions]

Triage summary

Labels applied: Area-Build-Rust, Area-Build-TypeScript, Area-SDK-Configuration

This issue is a design-evaluation task covering the schema/codegen pipeline — specifically whether mxc_schema_gen / wxc_common::ts_emit (Rust build tooling), the generated TypeScript wire types, and the SDK configuration schema could be replaced by a FlatBuffers/flatc-driven pipeline. All three area labels are applicable.

Owner assignment: No owner was assigned — the existing assignment map does not include an owner whose primary area is schema/codegen tooling. The individuals already engaged (@MGudgin as author, @bbonaby as the reviewer who raised the original concern in #580) are likely the natural drivers of this evaluation.

Needs-Triage has been removed.

Generated by 🏷️ Issue Triage for #613 · 24.6 AIC · ⌖ 5.87 AIC · ⊞ 6K · ◷

[github-actions]

Triage summary

Labels applied: Area-Executor-Schema (the core ask is evaluating the schema codegen pipeline — mxc_schema_gen / JSON schema generation from the Rust wire model), Area-Test-SDK (the issue explicitly references the SDK conformance tests: sdk/tests/unit/conformance-helpers.ts, wire-conformance*.test.ts). Existing labels Area-SDK-Configuration, Area-Build-Rust, and Area-Build-TypeScript remain in place.

Owner assigned: None — no entry in the owner assignment map covers SDK/schema codegen tooling specifically.

Needs-Triage: Removed (labels were applied).

Generated by 🏷️ Issue Triage for #613 · 26.1 AIC · ⌖ 6.37 AIC · ⊞ 6K · ◷