ci: share codegen output across jobs via artifact

[eugypalu]

Closes #134.

The codegen job is the single place that runs scripts/codegen.sh (and therefore the only job that builds the Rust crate to produce the rustdoc JSON). It uploads the generated TypeScript surface as a codegen-output artifact:

• js/packages/truapi/src/generated
• js/packages/truapi/src/playground/codegen
• js/packages/truapi/src/explorer/codegen + src/explorer/versions.ts
• js/packages/truapi-host/src/generated
• playground/test/generated

The downstream jobs (ts-client, playground, explorer) download that artifact before npm ci. With the generated files already present, scripts/ensure-generated.sh short-circuits, so npm ci/npm run build compile the client with tsc alone and never invoke codegen.sh.

Because those jobs no longer touch Rust, the dtolnay/rust-toolchain and Swatinem/rust-cache steps are dropped from them, and the explicit ./scripts/codegen.sh invocations in playground and explorer are removed. ts-client now declares needs: codegen so the artifact is available when it runs.

[pgherveou]

Review: share codegen output across jobs via artifact

Summary. The codegen job becomes the single place that runs scripts/codegen.sh (and thus the only job that builds the Rust crate for rustdoc JSON). It uploads the generated TypeScript surface as the codegen-output artifact; ts-client, playground, explorer, and e2e download it before npm ci, so ensure-generated.sh short-circuits and those jobs compile with tsc alone. The Rust toolchain + cache steps and the explicit ./scripts/codegen.sh calls are dropped from the downstream jobs, and a new TRUAPI_REQUIRE_GENERATED=1 guard makes ensure-generated.sh fail loudly (instead of silently re-running codegen) when the artifact didn't restore the expected files.

Why all three mechanisms are needed (not just needs:): GitHub Actions jobs run on separate ephemeral runners with no shared filesystem, and the generated files are gitignored, so needs: alone transfers nothing — a downstream job would check out a tree with no generated files. The artifact is the actual data transfer; needs: only orders the jobs; TRUAPI_REQUIRE_GENERATED=1 is a fail-fast guard that turns "files missing → silently run codegen → cryptic cargo error (toolchain now removed)" into a clear "add the path to the upload-artifact step" message.

Findings

#	Severity	File	Description
1	Info	.github/workflows/ci.yml	TRUAPI_REQUIRE_GENERATED: 1 is repeated across 4 jobs. Could be hoisted to a workflow-level env:. Harmless to set globally: the rust job never runs ensure-generated.sh, and codegen always produces the files so the guard never trips. DRY nit only.
2	Info	.github/workflows/ci.yml	The graph now serializes codegen → ts-client → {playground, explorer} → e2e. This trades parallelism for not rebuilding Rust 4×; net win, but codegen is now a hard gate on everything downstream.

Verified

• Artifact paths cover every required file. Both ensure-generated.sh checklists (truapi: src/generated/{client,types,wire-table}.ts, playground/codegen/services.ts, explorer/codegen/types.ts, explorer/versions.ts, playground/test/generated/examples/*.ts; host: server.ts, types-by-version.ts) are fully covered by the six upload paths.
• Path consistency. codegen.sh writes examples to playground/test/generated/examples, matching both the ensure-generated check and the upload path.
• upload-artifact@v4 least-common-ancestor behavior preserves repo-root-relative structure (paths span js/... and playground/...), so download restores files to the correct locations.
• Dependency chain reaches codegen transitively from every artifact consumer.
• if-no-files-found: error and retention-days: 1 are appropriate.

Verdict: Mergeable. Clean PR, satisfies #134 (single Rust build, generated surface shared via artifact). The two items above are Info-only. A fresh CI run is currently in progress on a diff identical to the previously-green run.

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Reviewed with assistance from Claude Code.

[pgherveou]

LGTM — clean artifact-sharing refactor for #134. Only Info-level nits (see review comment). Verified artifact paths cover all required generated files and the dependency chain reaches codegen.