Δ3 — Run-dir → S3 incremental sidecar (keep amico-run thin)

[jack-champagne]

C0. A sidecar on the EC2 box tails the run-dir and syncs run.toml→iter_*.png→run.log→result.toml→FINISHED to s3://…/<tenant>/<task_id>/ as produced (cheap PUTs). amico-run stays thin (D9) — the sidecar, not amico-run, owns the upload. This is what enables poll-on-demand live-ish frames.

Acceptance (TDD): during a solve, S3 shows a new iter_*.png within one poll interval of being written on the box; FINISHED is the last object PUT even on solve failure; amico-run's source is unchanged.

⛔ Gate: blocked by the wk-3 freeze — run-dir contract + SchemaPackage v0 (amicode #15 + the #28–31 stack). RemoteExecutor/the S3 layout is the run-dir contract, so do not start until that lands.

📄 Refs: Spec armonissima/specs/spec-20260628-amicode-cloud-solve-service.md (Δ3) · phased plan §5a (plan-20260603-124231-amicode-phased-build) · aws-infra/INFRASTRUCTURE.md → The Analysis Pipeline (reuse step_function/ec2_launch_template/dynamodb/runner_image).

Evolve, not build — a working v0 (the aws-infra Analysis Pipeline) already does size→S/M/L EC2→julia→S3→email→terminate. Validate on staging (mirrors prod), then two-step promote.

🏗 Implementation repo: aws-infra (Terraform / lambda / Image Builder). Infra-side reference: harmoniqs/aws-infra#126.

[jack-champagne]

Protocol note (post-#67; see #58): the live per-iter frame is now pulse DATA in run.log (AMICODE_PULSE lines), not iter_*.png. Prioritize run.log in the incremental sync (it carries the live frame + stats); iter_*.png are still produced by the callback but no longer drive the live view (vestigial for live — keep only for the final/publication frame). Sync order run.toml→run.log→result.toml→FINISHED stands.