ADR 0076: the SDK is a published package the toolchain resolves by version

Records the decision the package-registry work turns on — the SDK is built on a
public base and published before the toolchain that consumes it, so nothing is
circular; mesh-tools stays the thin toolchain base but resolves the SDK by
version. Reconciles docs 12/17/22 and indexes the record.

Claude-Session: https://claude.ai/code/session_01D6qtiYU3P9jk3pnAXyAFyx

03-DESIGN/01-to-be/22-the-work-ahead.md

@@ -63,6 +63,17 @@ registry. Nothing installs one, so the SDK comes from a git URL (issue 053). Nee
 **Done when.** A module builds against the SDK resolved from the mesh's own registry, and issue 053
 closes.
 
+**Where it stands (2026-09-16).** The decision the bootstrap turned on is settled and recorded
+([ADR 0076](../../02-DECISIONS/0076-the-sdk-is-a-published-package.md)): the SDK is a published
+package, built on a public base image and published before the toolchain that consumes it; mesh-tools
+stays the thin toolchain base but `npm ci`s the SDK by version. On the code, the builder now resolves
+a package-registry credential — from a binding the mesh writes or from the environment for a hand-run
+or bootstrap build — and injects it into an image build as a buildkit secret, never a layer, so a
+token is not baked into the toolchain image. Unit-tested. Still ahead: gitea serving the registry in
+full with a provisioner that mints tokens (2.1), the SDK built and published by the mesh (2.2), the
+mesh-tools manifest flipped off the git URL to `npm ci` by version (2.3), and the genesis step that
+raises gitea and publishes the SDK before the base build. Those close together in one lab run.
+
 ## Phase 3 — nothing is special after installation
 
 **Why last.** The hardest and riskiest, and it needs everything above: an installer that completes,