Forward cloud AMICODE_PULSE into the run inspector

[jack-champagne]

What

Adds a /pulse poll lane to RemoteExecutor so a cloud solve's progressive pulse reaches the run inspector — the last missing piece for "submit a cloud solve → watch the pulse animate," which works locally today but not for cloud runs.

Why

The poll pump already forwards AMICODE_ITER (/stats) and PNG frames (/frames) into the mirror run.log, but never the AMICODE_PULSE_META / AMICODE_PULSE lines. The render side (native type-aware pulse plot, #224) tails these off run.log for local solves — it just never received them for cloud runs, so the cloud pulse plot stayed at "No pulse data."

How

A /pulse lane that mirrors /stats exactly (remote_executor.ts):

• relay AMICODE_PULSE_META once (it carries no iter),
• relay each new AMICODE_PULSE line on the iteration high-water (the API re-serves full history each poll),
• verbatim — so the a= drive knots and the d= derivative tail reach the plotter unaltered.
• Best-effort like stats/frames: a runner/API without /pulse 404s → swallowed → no-op, so this is safe to merge before the cloud endpoint exists (degrades exactly like the pre-feat(hp): cloud-only enforcement + cloud iters/frames reach the Run Inspector #219 state).

Scope

Client-only. Does not touch the solve templates / solver output (@rchari's current lane) — this only relays whatever pulse the solve already emits.

⚠️ Requires a cloud companion (for @rchari to wire, or a follow-up)

GET /solves/{id}/pulse in the solves_poll lambda (aws-infra), ~10 lines mirroring _stats:

# grep AMICODE_PULSE_META + AMICODE_PULSE out of the S3-synced run.log
for line in log.splitlines():
    if "AMICODE_PULSE" in line:
        pulse.append({"raw": line.strip()})
return _resp(200, {"task_id": task_id, "pulse": pulse})

Response shape {task_id, pulse: [{raw}], submitter} — identical to /stats. Until it ships, this lane is inert (no-op), not broken.

Tests

FakeCloud now serves /pulse (mirrors the live wire shape); new test asserts the meta line is relayed once and pulse frames dedupe on the iteration high-water in run.log. Full amico-run suite green (939 passed); build + typecheck + prettier clean.

End-to-end status (for context)

This is client gap #1 of the "Altissimo cloud solve → run inspector" flow. Remaining: (2) an Altissimo emitter branch in the solve template (Raghav's #2 — coarse, per-outer-iteration), and (3) an amicode release carrying #219 + #224 + this.