Replace the external `@pnpm/registry-mock` (Verdaccio) test dependency with an in-repo, in-process registry that serves package fixtures to **both** the pacquet Rust tests and the pnpm CLI (Jest) tests. No separately managed registry process is needed.
### How it works
- **Fixtures** live at `registry/.fixtures/packages/<name>/<version>/…`, moved verbatim from [`pnpm/registry-mock`](https://github.com/pnpm/registry-mock) (keyed by each `package.json`'s `name`+`version`).
- **`pnpm-registry-fixtures`** builds verdaccio-shaped storage from those fixtures; the in-tree **`pnpm-registry`** crate serves it.
- Files whose names differ only by case (`@pnpm.e2e/with-same-file-in-different-cases`) and `bundleDependencies` trees are composed **in memory** by the builder, since neither can be committed to the working tree.
- **pacquet**: `pacquet-testing-utils`' `TestRegistry` starts the server lazily (once per process) in proxy mode, serving `@pnpm.e2e` fixtures locally and falling through to the npm uplink for real packages (`is-positive`, `is-negative`, …) — matching how registry-mock behaved.
- **pnpm CLI**: the `with-registry` Jest `globalSetup` builds storage from the fixtures via the new `pnpm-registry-prepare` binary (built from source in the Test CI job) and serves it with `pnpm-registry`. `REGISTRY_MOCK_PORT` / `REGISTRY_MOCK_CREDENTIALS` / `getIntegrity` now come from `@pnpm/testing.registry-mock`.
### Result
`@pnpm/registry-mock` is removed from every manifest, the catalog, and `packageExtensions`; `cargo test` / `cargo nextest run` / `just test` and the pnpm CLI Jest suites all run registry-backed tests without launching Verdaccio.
Library packages had `prepublishOnly: pn compile`, which expands to
`tsgo --build && pn lint --fix`. During `pn release` that runs eslint
against ~150 packages for no benefit — the code has already been linted
in CI and the release flow's upfront compile has already built dist/.
Switch lib prepublishOnly to a bare `tsgo --build` so the safety-net
compile stays but the per-package eslint cost is gone.
## Summary
Adds an opt-in **pnpm agent** server that resolves dependencies server-side and streams only the files missing from the client's content-addressable store.
- **`@pnpm/agent.server`** — multi-process HTTP server (Node.js `cluster`) with SQLite-backed metadata and file caches
- **`@pnpm/agent.client`** — streams an NDJSON response, dispatches worker threads to fetch files while the server is still resolving
- **New config**: `agent` in `pnpm-workspace.yaml` (opt-in)
## How it works
1. Client reads integrity hashes from its local store index
2. Sends `POST /v1/install` with dependencies + store integrities
3. Server resolves the dependency tree using pnpm's `install({ lockfileOnly: true })`, with a SQLite-backed `PackageMetaCache` for fast repeat resolution
4. As each package resolves, a wrapped `storeController.requestPackage` looks up its files and immediately streams digests the client is missing (NDJSON `D` lines)
5. Client reads the stream line by line; digest batches fill up and dispatch worker threads to `POST /v1/files` — file downloads overlap with server-side resolution
6. After resolution, server sends index entries (`I` lines) and lockfile (`L` line)
7. Client writes index entries to store, then runs headless install with a wrapped `fetchPackage` that calls `readPkgFromCafs` with `verifyStoreIntegrity: false` (files are trusted from the agent)
8. `/v1/files` response is gzip-streamed (274MB → ~80MB) — server pipes through `createGzip`, worker pipes through `createGunzip`, parsing and writing files to CAFS as data arrives
## Performance
1351-package project, cold local store, warm server (localhost):
| Scenario | Time |
|----------|------|
| Vanilla pnpm install (cold OS cache) | ~48s |
| Vanilla pnpm install (warm OS cache) | ~34s |
| With pnpm agent (consistent) | **~33s** |
### Key optimizations
1. **SQLite metadata cache** — server-side resolution drops from ~3.4s to ~0.9s
2. **SQLite file store** — consistent read performance regardless of OS file cache state
3. **Streaming `/v1/install`** — file digests stream during resolution, downloads start before resolution finishes
4. **Gzip-streamed `/v1/files`** — whole-stream gzip (274MB → ~80MB), significant savings on remote servers
5. **Worker-thread streaming HTTP** — workers pipe gzip → parse → write to CAFS as data arrives, no buffering
6. **No rehashing** — server-provided digests used directly, skipping 33K SHA-512 computations
7. **No re-verification** — wrapped `fetchPackage` calls `readPkgFromCafs` with `verifyStoreIntegrity: false`
8. **Direct `writeFileSync` with `wx`** — no stat + temp + rename
9. **Pre-packed msgpack** — server sends raw store index buffers, client writes directly to SQLite
10. **WAL checkpoint** — ensures store index entries written by agent are visible to headless install's worker threads
## Usage
Start the server:
```bash
node agent/server/lib/bin.js
```
Configure in `pnpm-workspace.yaml`:
```yaml
agent: http://localhost:4873
```
