feat: patchwork-worker library for connecting to generic workers

[grjte]

This creates a library for creating and connecting to workers by passing a transferable stream pair (readable, writable) to consumers that want to connect to the worker.

The motivation for this library is to enable packages inside of an iframe or isolated zone to connect to a worker that is initiated from the host. For example, when using chat from inside isolation, running the llm requires a worker which isn't powerful enough if initiated with an iframe context (e.g. for local llm it can't download the model or run it). Instead, it can request a worker running in the host and then get a stream pair to use for communication.

The rest of the architecture for the example llm case is separate from this library

[patchcrow]

✅ Patchwork glance ready

https://patchwork-preview-69--patchwork-base.netlify.app

Patchwork from inkandswitch/patchwork.inkandswitch.com, packages from this PR at 3e02807.

build-info.json

[Copilot]

Copilot review overview

🟡 Changes recommended

Connection lifecycle races, leaked request state, and swallowed transport failures can reject new requests or leave them hanging.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 3 · 2

Open (5)

• Include the required provider integration or document it as unavailable · New
• Catch synchronous exceptions from spec.open · New
• Prevent stale connections from resetting replacement connections · New
• Fix the broken llm-host documentation link · New
• Export the complete IO type in WorkerSpec · New

What changed in this PR

Introduces a standalone worker transport library for host-realm workers accessed through transferable streams.

Changes:

• Adds worker discovery, sessions, typed clients, and serving.
• Adds lifecycle, multiplexing, abort, and failure tests.
• Adds package configuration, declarations, and documentation.

File	Description
.gitignore	Excludes generated artifacts.
README.md	Documents architecture and APIs.
client.js	Resolves typed worker clients.
client.test.js	Tests client resolution.
connect.js	Implements provider discovery.
connect.test.js	Tests connections and sessions.
index.js	Exposes public API.
package.json	Defines package metadata and exports.
pnpm-lock.yaml	Locks dependencies.
pnpm-workspace.yaml	Configures pnpm.
serve.js	Implements host worker transport.
serve.test.js	Tests serving and teardown.
session.js	Implements multiplexed sessions.
tsconfig.json	Configures declaration generation.
types/​client.d.ts	Declares client API.
types/​connect.d.ts	Declares connection API.
types/​index.d.ts	Declares package exports.
types/​serve.d.ts	Declares serving API.
types/​session.d.ts	Declares session API.
vitest.config.ts	Configures tests.

Files not reviewed (1)

• libraries/patchwork-worker/pnpm-lock.yaml: Generated file

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