Grilling: lock MVP Work* attribute and builder API surface sketch

[cursor]

Part of #300

Blocked by: #301

Question

Lock the MVP public surface sketch for Fork–Join Work Graph sufficient to write the Spec: holder/graph attribute shape, [WorkStep] / DependsOn, IWorkStep<TContext> async contract, WorkGraphBuilder / IWorkGraph manual path, and generated {Name}WorkGraph / {Name}WorkStepKeys responsibilities.

Respect map #300 locked preferences (shared TContext, string ids, async-only, dual path, Work* naming). Do not implement code.

[Skymly]

Resolution — Grilling: lock MVP Work* attribute and builder API surface sketch

Locked MVP public surface (sufficient for Spec prose). No implementation.

Schema placement

• Holder + step types: marker holder + [WorkGraph<TContext>]; each step is a type implementing IWorkStep<TContext> with [WorkStep].

Graph membership

• Steps explicitly reference the holder: [WorkStep(typeof(Holder), ...)] (not TContext-only aggregation, not holder type lists, not nested-type-only).

Holder attribute

• [WorkGraph<TContext>] on the holder (not GenerateWorkGraph*, not non-generic typeof context).
• Generated names derive from the holder type name ({Name}WorkGraph / {Name}WorkStepKeys); suffix-stripping is a Spec wording detail, not reopened here.

[WorkStep] shape

• Holder as positional typeof, plus named Id and DependsOn (string[]), aligned with map Wayfinder: Fork–Join Work Graph MVP Spec #300.

IWorkStep<TContext>

• ValueTask ExecuteAsync(TContext context, CancellationToken cancellationToken) only (no result wrapper, no sync twin in MVP).
• Outputs via shared TContext; failures via exceptions (fail-fast per map).

Manual path

• WorkGraphBuilder<TContext> fluent .Add(...) → Build() (runtime validation) → IWorkGraph<TContext>.RunAsync(ctx, ct).
• RunAsync return shape / Dop knobs deferred to Grilling: lock MVP knobs and Phase 2+ Non-goals list #305.

Generated responsibilities

• {Name}WorkStepKeys: public const string per step id.
• {Name}WorkGraph: static facade Create(resolver | map) that fills the builder and Build()s — not parameterless-only Instance, not MVP RegisterDi.

Glossary

• CONTEXT.md updated: Work Graph, work graph holder, work step, work step id, work graph (runtime).

Deferred (other tickets / Spec)

• Diagnostic matrix (Grilling: lock MVP Work Graph diagnostic matrix #304), MVP knobs / Non-goals list (Grilling: lock MVP knobs and Phase 2+ Non-goals list #305), stub prototype (Prototype: stub Work* API outline for Spec reaction #306), Spec filing (Task: file Spec: Fork–Join Work Graph (F3 Top-3) issue #307).

[Skymly]

Resolved: MVP Work* surface locked; see resolution comment.