release(v4.0.0): Shade GA — V3.x consolidation + audit prep

V3.1 → V3.12 consolidated and tagged for the first GA release. Wire
format unchanged from 0.4.x — 4.0 peers interoperate with 0.4.x peers
byte-for-byte. The version bump is semantic: audit-cycle complete,
opt-in surface fully exposed, threat model refreshed for every new
surface.

Highlights:
- All 24 @shade/* packages bumped to 4.0.0 in lockstep.
- CHANGELOG 4.0.0 section is the canonical manifest of what landed.
- THREAT-MODEL extended (§10 fingerprint gates, §11 WebRTC P2P, §12
  Web-Worker boundary) + residual-risks table refreshed.
- OpenAPI now covers all 27 routes: prekey, transfer, KT, inbox,
  bridge, observer, /metrics, /healthz, /ready.
- MIGRATION 0.3.x → 4.0 documented + smoke-tested against
  shade migrate-storage on a real SQLite DB.
- docs/audit/REVIEW-BUNDLE.md + SCOPE.md ready for external reviewer.
- scripts/soak.ts harness for the GA-stable 2-week soak window.
- All V*.md plans archived under docs/archive/ with Status: Done.
- Voice/Video carved out into V5.0; 4.0 audit focuses on the frozen
  non-realtime stack.

Tests: TS 1000/1000 + Kotlin 11/11 cross-platform vectors green.
Docker: gt.zyon.no/stian/shade-prekey:4.0.0 builds and reports
  version 4.0.0 on /health.

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

packages/shade-transport-webrtc/tests/transport.test.ts

@@ -0,0 +1,193 @@
+/**
+ * End-to-end test of `WebRtcTransferTransport` against the manager + memory
+ * factory. Exercises the same `ITransferTransport` API the engine calls
+ * (`probe`, `sendChunk`, `fetchResumeState`).
+ */
+import { afterEach, describe, expect, it } from 'bun:test';
+import { MemoryRtcFactory } from '../src/memory-rtc.js';
+import { MemoryShadeBridge, WebRtcSignalingChannel } from '../src/signaling.js';
+import { WebRtcConnectionManager } from '../src/manager.js';
+import {
+  DEFAULT_MAX_DATACHANNEL_MESSAGE,
+  WebRtcTransferTransport,
+} from '../src/transport.js';
+import { streamIdBytesToString } from '../src/wire.js';
+
+afterEach(() => {
+  MemoryRtcFactory.reset();
+});
+
+function paired(opts: {
+  bobReceiver: import('../src/connection.js').WebRtcReceiverHooks;
+}): {
+  alice: WebRtcConnectionManager;
+  bob: WebRtcConnectionManager;
+  aliceTransport: WebRtcTransferTransport;
+} {
+  const factory = new MemoryRtcFactory();
+  const { a, b } = MemoryShadeBridge.linked('alice', 'bob');
+  const aliceSig = new WebRtcSignalingChannel(a);
+  const bobSig = new WebRtcSignalingChannel(b);
+  const alice = new WebRtcConnectionManager({ factory, signaling: aliceSig });
+  const bob = new WebRtcConnectionManager({
+    factory,
+    signaling: bobSig,
+    receiver: opts.bobReceiver,
+  });
+  const aliceTransport = new WebRtcTransferTransport({ manager: alice });
+  return { alice, bob, aliceTransport };
+}
+
+function makeStreamId(): string {
+  const b = new Uint8Array(16);
+  globalThis.crypto.getRandomValues(b);
+  return streamIdBytesToString(b);
+}
+
+describe('WebRtcTransferTransport', () => {
+  it('probe opens the peer connection', async () => {
+    const { alice, bob, aliceTransport } = paired({
+      bobReceiver: {
+        async onChunk() {
+          return { lastSeq: 0 };
+        },
+        async onResumeQuery() {
+          return null;
+        },
+      },
+    });
+    await aliceTransport.probe('bob');
+    expect(alice.isConnected('bob')).toBe(true);
+    alice.destroy();
+    bob.destroy();
+  });
+
+  it('sendChunk routes envelope to receiver and returns the ack', async () => {
+    let received: { laneId: number; seq: bigint; bytes: number } | null = null;
+    const { alice, bob, aliceTransport } = paired({
+      bobReceiver: {
+        async onChunk(_from, _streamId, laneId, seq, envelope) {
+          received = { laneId, seq, bytes: envelope.length };
+          return { lastSeq: Number(seq), bytesReceived: envelope.length };
+        },
+        async onResumeQuery() {
+          return null;
+        },
+      },
+    });
+
+    const streamId = makeStreamId();
+    const envelope = new Uint8Array(2048);
+    envelope.fill(0x42);
+    const ack = await aliceTransport.sendChunk('bob', streamId, 1, 5n, envelope);
+    expect(ack.lastSeq).toBe(5);
+    expect(ack.bytesReceived).toBe(2048);
+    expect(received).not.toBeNull();
+    expect(received!.laneId).toBe(1);
+    expect(received!.seq).toBe(5n);
+    expect(received!.bytes).toBe(2048);
+
+    alice.destroy();
+    bob.destroy();
+  });
+
+  it('rejects oversized envelopes that would exceed the data channel cap', async () => {
+    const { alice, bob, aliceTransport } = paired({
+      bobReceiver: {
+        async onChunk() {
+          return { lastSeq: 0 };
+        },
+        async onResumeQuery() {
+          return null;
+        },
+      },
+    });
+    const streamId = makeStreamId();
+    const huge = new Uint8Array(DEFAULT_MAX_DATACHANNEL_MESSAGE + 1);
+    await expect(aliceTransport.sendChunk('bob', streamId, 0, 0n, huge)).rejects.toThrow(
+      /frame too large/,
+    );
+    alice.destroy();
+    bob.destroy();
+  });
+
+  it('fetchResumeState returns parsed state when the receiver knows the stream', async () => {
+    const { alice, bob, aliceTransport } = paired({
+      bobReceiver: {
+        async onChunk() {
+          return { lastSeq: 0 };
+        },
+        async onResumeQuery(_from, streamId) {
+          return {
+            streamId,
+            lanes: [
+              { laneId: 0, lastSeqAcked: 11 },
+              { laneId: 1, lastSeqAcked: 4 },
+            ],
+          };
+        },
+      },
+    });
+    const sid = makeStreamId();
+    const state = await aliceTransport.fetchResumeState('bob', sid);
+    expect(state).not.toBeNull();
+    expect(state!.streamId).toBe(sid);
+    expect(state!.lanes[0]!.lastSeqAcked).toBe(11);
+    expect(state!.lanes[1]!.lastSeqAcked).toBe(4);
+    alice.destroy();
+    bob.destroy();
+  });
+
+  it('fetchResumeState returns null when the peer reports not found', async () => {
+    const { alice, bob, aliceTransport } = paired({
+      bobReceiver: {
+        async onChunk() {
+          return { lastSeq: 0 };
+        },
+        async onResumeQuery() {
+          return null;
+        },
+      },
+    });
+    const state = await aliceTransport.fetchResumeState('bob', makeStreamId());
+    expect(state).toBeNull();
+    alice.destroy();
+    bob.destroy();
+  });
+
+  it('multiple in-flight requests interleave correctly via requestId correlation', async () => {
+    let inflight = 0;
+    let maxInflight = 0;
+    const { alice, bob, aliceTransport } = paired({
+      bobReceiver: {
+        async onChunk(_from, _streamId, _laneId, seq) {
+          inflight++;
+          if (inflight > maxInflight) maxInflight = inflight;
+          // Stagger response so request ordering doesn't trivially match
+          // response ordering.
+          await new Promise<void>((resolve) =>
+            setTimeout(resolve, Number(seq % 5n) * 5),
+          );
+          inflight--;
+          return { lastSeq: Number(seq), bytesReceived: 0 };
+        },
+        async onResumeQuery() {
+          return null;
+        },
+      },
+    });
+    const streamId = makeStreamId();
+    const acks = await Promise.all(
+      Array.from({ length: 12 }, (_, i) =>
+        aliceTransport.sendChunk('bob', streamId, i % 4, BigInt(i), new Uint8Array(8)),
+      ),
+    );
+    // Each ack matches its request seq (round-trip via requestId).
+    for (let i = 0; i < acks.length; i++) {
+      expect(acks[i]!.lastSeq).toBe(i);
+    }
+    expect(maxInflight).toBeGreaterThan(1);
+    alice.destroy();
+    bob.destroy();
+  });
+});