release(v4.2.0): pull-mode streams for browser @shade/files

4.1.0's HTTP RPC for browsers capped at inline payloads (≤ 256 KiB).
4.2.0 unlocks streams: server queues outbound chunks + control
envelopes per peer, browser long-polls the queue. Browser-to-server
writes ride the existing /v1/transfer/<id>/chunk POST routes
unchanged.

For Dispatch this unlocks mod-jar uploads (50 MB) and world-backup
downloads (100+ MB) — the actual reason browser-side @shade/files
matters.

### New API

@shade/sdk:
- shade.transferQueueRoute(opts?) — Hono app with /queue +
  /v1/transfer/* routes. Auto-configures the queue transport.
- shade.configureTransfers extended: transport + envelopeTransport
  override slots; resolveBaseUrl optional when both supplied.

@shade/transfer:
- OutboundQueue — per-peer monotonic event log with long-poll
  semantics, idle-eviction GC, ring-buffered to maxEventsPerPeer.
- QueueTransferTransport — enqueues instead of POSTing.

@shade/files:
- httpClient({ outboundQueueUrl, transferBaseUrl }) — when set,
  starts a long-poll drainer + builds a streams-bridge. fs.read /
  fs.write of >256 KiB work end-to-end.
- startQueueDrainer(shade, opts) — exported helper for advanced
  consumers driving their own drainer.

### Implementation notes

- ClientStreamsBridge's TransformStream had HWM=0 by default which
  stalled the drainer's await chain at chunk 4 (writer.write pended
  before the consumer's reader was attached). Bumped to HWM=64 so
  the receive loop can buffer ahead of the consumer.

### Tests

3 new integration tests in tests/integration/http-rpc-streams.test.ts:
4 MiB streamed read round-trip, inline-only error path, idle-timeout
long-poll behaviour.

Wire-compatible. Source-compatible. Lockstep bump to 4.2.0.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shade-files/tests/integration/http-rpc-streams.test.ts

@@ -0,0 +1,208 @@
+import { describe, expect, test } from 'bun:test';
+import { createShade } from '@shade/sdk';
+import {
+  createPrekeyServer,
+  MemoryPrekeyStore,
+  PrekeyServerEvents,
+} from '@shade/server';
+import { SubtleCryptoProvider } from '@shade/crypto-web';
+import { Hono } from 'hono';
+
+const crypto = new SubtleCryptoProvider();
+
+/**
+ * Stand up the full pull-mode rig:
+ *   - Prekey server (for X3DH)
+ *   - Bob: file handler + rpcRoute + transferQueueRoute, all on one server
+ *   - Alice: httpClient with outboundQueueUrl + transferBaseUrl wired
+ *
+ * Returns Alice's `FileClient`, which speaks browser-style: ONE base URL,
+ * no inbound listener, streams supported via long-poll.
+ */
+async function setupPullRig(opts: {
+  bobHandler: Parameters<NonNullable<Awaited<ReturnType<typeof createShade>>['files']>['serve']>[0];
+}) {
+  const prekey = createPrekeyServer({
+    crypto,
+    store: new MemoryPrekeyStore(),
+    disableRateLimit: true,
+    events: new PrekeyServerEvents(),
+  });
+  const prekeyServer = Bun.serve({ port: 0, fetch: prekey.fetch });
+  const prekeyUrl = `http://localhost:${prekeyServer.port}`;
+
+  const alice = await createShade({ prekeyServer: prekeyUrl, address: 'alice' });
+  const bob = await createShade({ prekeyServer: prekeyUrl, address: 'bob' });
+
+  // Bob: queue-route FIRST (configures bob's transports), then files.serve.
+  const queueRoute = await bob.transferQueueRoute({ blockMs: 1_500 });
+  await bob.files.serve(opts.bobHandler);
+  const rpcRoute = bob.files.rpcRoute({ acceptFirstMessage: true });
+
+  const app = new Hono();
+  app.route('/', queueRoute);
+  app.route('/', rpcRoute);
+
+  const bobServer = Bun.serve({ port: 0, fetch: app.fetch });
+  const baseUrl = `http://localhost:${bobServer.port}`;
+
+  const fs = alice.files.httpClient('bob', {
+    rpcUrl: `${baseUrl}/rpc`,
+    outboundQueueUrl: `${baseUrl}/queue`,
+    transferBaseUrl: baseUrl,
+    defaultTimeoutMs: 10_000,
+    queueBlockMs: 1_000,
+  });
+
+  return {
+    alice,
+    bob,
+    fs,
+    baseUrl,
+    teardown: async () => {
+      fs.close();
+      await alice.shutdown();
+      await bob.shutdown();
+      bobServer.stop();
+      prekeyServer.stop();
+    },
+  };
+}
+
+describe('@shade/files HTTP RPC — pull-mode streams', () => {
+  test('streamed read (4 MiB) via long-poll queue', async () => {
+    const payload = new Uint8Array(4 * 1024 * 1024);
+    for (let i = 0; i < payload.length; i++) payload[i] = (i * 97) & 0xff;
+
+    const rig = await setupPullRig({
+      bobHandler: {
+        read: async () => {
+          // Return the payload as a streamed read so the rpc-handler
+          // promotes it via the streams-bridge into a transfer.
+          const stream = new ReadableStream<Uint8Array>({
+            start(controller) {
+              const CHUNK = 256 * 1024;
+              for (let off = 0; off < payload.byteLength; off += CHUNK) {
+                controller.enqueue(payload.slice(off, Math.min(off + CHUNK, payload.byteLength)));
+              }
+              controller.close();
+            },
+          });
+          // Need a precomputed sha256 for streamed reads. Use the
+          // crypto provider's sha256 directly.
+          const digest = new Uint8Array(await globalThis.crypto.subtle.digest('SHA-256', payload));
+          const sha256Hex = Array.from(digest, (b) => b.toString(16).padStart(2, '0')).join('');
+          return {
+            kind: 'streams' as const,
+            stream,
+            size: payload.byteLength,
+            sha256: sha256Hex,
+            contentType: 'application/octet-stream',
+          };
+        },
+      },
+    });
+
+    try {
+      const result = await rig.fs.read('/big.bin');
+      expect(result.kind).toBe('streams');
+      if (result.kind !== 'streams') return;
+
+      // Drain the stream and compare.
+      const reader = result.stream.getReader();
+      const got = new Uint8Array(payload.byteLength);
+      let offset = 0;
+      while (true) {
+        const { value, done } = await reader.read();
+        if (done) break;
+        if (value !== undefined) {
+          got.set(value, offset);
+          offset += value.byteLength;
+        }
+      }
+      reader.releaseLock();
+      await result.done();
+
+      expect(offset).toBe(payload.byteLength);
+      // Compare in 64KiB strides for speed.
+      let mismatch = -1;
+      for (let i = 0; i < payload.byteLength; i++) {
+        if (got[i] !== payload[i]) {
+          mismatch = i;
+          break;
+        }
+      }
+      expect(mismatch).toBe(-1);
+    } finally {
+      await rig.teardown();
+    }
+  }, 30_000);
+
+  test('streamed read fails with clear error when outboundQueueUrl is omitted', async () => {
+    const rig = await setupPullRig({
+      bobHandler: {
+        read: async () => {
+          const stream = new ReadableStream<Uint8Array>({
+            start(c) {
+              c.enqueue(new Uint8Array(512 * 1024));
+              c.close();
+            },
+          });
+          const digest = new Uint8Array(await globalThis.crypto.subtle.digest('SHA-256', new Uint8Array(512 * 1024)));
+          const sha256Hex = Array.from(digest, (b) => b.toString(16).padStart(2, '0')).join('');
+          return {
+            kind: 'streams' as const,
+            stream,
+            size: 512 * 1024,
+            sha256: sha256Hex,
+          };
+        },
+      },
+    });
+    // Tear down the rig's drainer so we can construct an inline-only client
+    rig.fs.close();
+
+    const inlineOnly = rig.alice.files.httpClient('bob', {
+      rpcUrl: `${rig.baseUrl}/rpc`,
+      defaultTimeoutMs: 10_000,
+    });
+    try {
+      await expect(inlineOnly.read('/big.bin')).rejects.toThrow(/streamed read/);
+    } finally {
+      inlineOnly.close();
+      await rig.teardown();
+    }
+  }, 15_000);
+
+  test('long-poll returns empty events on idle timeout', async () => {
+    const rig = await setupPullRig({
+      bobHandler: {
+        stat: async () => ({
+          name: '_',
+          kind: 'dir' as const,
+          size: 0,
+          mtime: 0,
+          metadata: {},
+        }),
+      },
+    });
+    try {
+      // Direct poll without any pending events — should return after blockMs.
+      const start = Date.now();
+      const res = await fetch(`${rig.baseUrl}/queue`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Shade-Sender-Address': 'alice',
+        },
+        body: JSON.stringify({ since: 0, blockMs: 500 }),
+      });
+      expect(res.status).toBe(200);
+      const body = (await res.json()) as { events: unknown[]; nextSince: number };
+      expect(body.events).toHaveLength(0);
+      expect(Date.now() - start).toBeGreaterThanOrEqual(400);
+    } finally {
+      await rig.teardown();
+    }
+  }, 10_000);
+});