Add a gated Known Limitations and Deferred Work section to every package README

Every packages/*/* README now carries a canonical '## Known Limitations and
Deferred Work' section: condensed, evidence-backed bullets for consumer-visible
gaps (unimplemented features, platform caveats, MVP cuts) and consciously
postponed work (TODO/FIXME/XXX markers, RFC deferrals still open). The ten
pre-existing ad-hoc variants ('What is NOT here (TODO)', 'Deferred',
'Limitations (MVP)', 'Known limitations (tracked TODOs)', ...) are normalized
into the canonical heading.

A new doc-sync gate, scripts/verify-readme-limitations.ts, enforces the shape:
exactly one limitations-like heading per package README, byte-equal to the
canonical h2, with at least one bullet; near-miss headings fail so variants
cannot creep back. Packages with genuinely nothing to declare (dsh-brand,
dsh-timeout, dsh-subagent-mock, dsh-app-boot) are whitelisted in the script and
must NOT carry the section; whitelist entries are validated against the scanned
package set so a rename fails loud.

Wired into the doc-sync chain (package.json) and the run-gates doc-sync leaf
set; the standing rule lands in packages/AGENTS.md and the adding-a-package
cookbook; decision record in
docs/rfc/implemented/process/2026-07-10-readme-known-limitations-gate.md
(RFC index regenerated).

Also fixes two stale '(deferred)' markers claiming dsh-compact-basic is
unimplemented (the dsh-compact seam README's package table and the seam's
module doc comment).

packages/code-runtime/code-runtime-worker/README.md

@@ -30,3 +30,11 @@ Every field is validated (positive numbers) and defaulted; there are no other tu
 ## The worker entry, unbuilt and built
 
 `worker.ts` is deliberately erasable-only TypeScript with type-only cross-package imports: unbuilt (vitest/tsx), the host spawns `src/worker.ts` directly and Node's native type stripping loads it; built, the entry ships as the sibling bundle `lib/worker.js` (its own tsdown entry). The built path is pinned by `tests/built-lib.e2e.ts`, the real-load-path guard from [docs/testing.md](../../../docs/testing.md).
+
+## Known Limitations and Deferred Work
+
+- **OS processes a program spawns survive termination** — `worker.terminate()` ends the thread only, weaker than bash-local's process-group kill; orphan cleanup is a deployment concern until a container backend exists.
+- **Type-strip rides Node's experimental `stripTypeScriptTypes` API** — the relied-on behavior is pinned by unit tests, with amaro/sucrase as named drop-in replacements if it shifts.
+- **`computeMs` expiry can overshoot by up to one poll interval** — busy time is sampled every 25 ms (an internal constant, deliberately not config).
+- **Programs get a five-method `console` shim** (`log`/`info`/`warn`/`error`/`debug`) — deliberately not Node's full console surface.
+- **A non-cloneable or oversize completion value does not cross as a value** — it arrives as a bounded, truncation-marked `util.inspect` rendering in `value`'s place.