[Core] Add Factory Pause Checkpoints

[MRayermannMSFT]

What

Adds token-scoped factory pause and durable checkpoint APIs to the Node.js SDK after the runtime contract lands. A paused attempt settles its waiter while resume preserves invocation limit overrides and execution identity.

Why

Factory authors need a safe checkpoint that stops spend without losing completed work. Token-scoped aborts stop an old attempt from cancelling a resumed attempt with the same run ID.

[github-actions]

Cross-SDK Consistency Review — PR #2537

Scope of changes: This PR touches only nodejs/src/factory.ts, nodejs/src/index.ts, nodejs/src/session.ts, and nodejs/test/factory.test.ts. It:

• Adds a new context.pause(key) / session.factory.pause(runId) checkpoint API to the experimental Agent Factories surface.
• Renames the public FactoryLimits type to FactoryLimitOverrides for RunOptions/ResumeOptions.limits.
• Adds a "paused" terminal run status and threads executionToken through abort().

Findings:

• ✅ No new cross-SDK inconsistency introduced. The "Agent Factories" feature (session.factory, defineFactory, context.pause, etc.) is currently implemented only in the Node.js/TypeScript SDK and is explicitly marked @experimental. There is no equivalent factory module/API surface in python/copilot/, go/, dotnet/src/, java/sdk/src/main/java/ (only Java's generated RPC types exist, no hand-written client wrapper), or rust/src/. Since this PR only extends an already Node-only experimental feature, it does not create a new divergence — the divergence (Node-only factory support) predates this PR.
• i️ FYI for future parity work: if/when Agent Factories graduates out of experimental status or is ported to other languages, this pause/checkpoint capability (and the FactoryLimitOverrides rename) should be included in that port for consistency (naming per language convention: pause/context.pause in Python, Pause/ctx.Pause in Go/.NET, pause in Java, pause in Rust).
• No API naming or behavior inconsistency was found relative to existing conventions within the Node.js SDK itself.

Conclusion: No inline comments needed — this PR maintains consistency with the current (Node-only) state of the experimental Agent Factories feature. No action required for other SDKs at this time.

Generated by SDK Consistency Review Agent for #2537 · copilot · sonnet50 · 40.7 AIC · ⌖ 12.2 AIC · ⊞ 8.3K · ◷

[Copilot]

Copilot review overview

🟡 Changes recommended

Public factory documentation remains inconsistent with resumable paused runs, and one new error message is malformed.

Get a fresh assessment by requesting another Copilot review.

Review tier: Balanced
Findings: 2

Open findings (2)

• Update public guidance for resumable paused runs · New
• Fix the malformed factory guard message · New

What changed in this PR

Adds Node.js factory pause checkpoints, resumable pause semantics, token-scoped cancellation, and nullable invocation-limit overrides.

Changes:

• Adds public and contextual pause APIs.
• Scopes aborts to execution tokens.
• Adds pause, resume-limit, and cancellation tests.

File	Description
nodejs/​src/​session.ts	Implements pause checkpoints and token-scoped aborts.
nodejs/​src/​factory.ts	Defines pause and limit-override APIs.
nodejs/​src/​index.ts	Exports the limit-override type.
nodejs/​test/​factory.test.ts	Tests pause, resume, and abort behavior.

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