fix(runtime): adopt kernel, idle wait and Codex recovery fixes

[rynfar]

Kernel pipe failures can crash the session worker, blocked queued inputs can spin in microtasks and starve daemon I/O, and stale Codex response IDs can fail an otherwise recoverable follow-up.

Selectively adopt upstream PrimeIntellect-ai#2213, PrimeIntellect-ai#2151 and PrimeIntellect-ai#2314 on Pylon's current Prime product branch. Kernel stream errors become diagnostics while existing write/exit handlers retain cleanup ownership. Idle waits park on the scheduler's busy predicate. Codex retries a stale continuation once with full context only before output, and binds cached continuation state to the producing socket.

Fixes #69. The adoption decisions and full source SHAs are in .pylon/features.yaml and .pylon/upstream-review.md; the complete upstream checkpoint stays at 1eee2938b. No protocol/schema/capability, Pylon ownership, scoped provider identity, publication, or managed installation changes.

Validation: 125 coding-agent tests passed, including the real isolated kernel pipe test, graceful shutdown and queue coverage; 25 Codex stream tests passed, including stale-chain retry, retry exhaustion, abort and no replay after streamed output. npm run check passes formatting/lint, TypeScript, installer and browser bundle checks. Review also checked input-wait wakeups and retained fork post-compaction settlement, existing kernel cleanup guards and pre-output-only retry semantics. Hosted CI is the final merge gate.

The maintainer authorized review and merge after green checks in the active Pylon conversation. A new immutable managed Prime build remains a separate delivery follow-up; this PR does not update running sessions or publish a release.

Model: GPT-6. Harness: Codex.

[rynfar]

Adversarial review completed at 1a3e6ac6dd6e04402a834d5fd6f8a745911095e4. No blocking findings remain. Checked stale continuation recovery before/after output and cancellation, socket cleanup, busy-state wake notifications, and preservation of Pylon's post-compaction settlement cleanup.

Local verification: 183 focused tests passed across kernel, queue, Codex, compaction continuation, correlated prompt lifecycle and request-abort regressions. npm run check passed, including the commit hook. Hosted code, kernel, Windows owned-session, artifact reproducibility and install checks are green; required publication crash suites are still running.

Maintainer approval is recorded from the active Pylon conversation: “keep going whatever needs to happen to get these reviewed and merged is the goal.” Merge remains conditional on all required checks passing for this head. Publication and installed-runtime changes remain separate follow-up work.