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/glare.test.ts

@@ -0,0 +1,49 @@
+/**
+ * Glare = both peers initiate at the same instant. The manager resolves
+ * deterministically: the address with the lexically-larger value yields
+ * to the smaller one's offer.
+ */
+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';
+
+afterEach(() => {
+  MemoryRtcFactory.reset();
+});
+
+describe('Glare resolution', () => {
+  it('two simultaneous getOrCreate() calls converge on a single connection', async () => {
+    const { a, b } = MemoryShadeBridge.linked('alice', 'bob');
+    const aliceSig = new WebRtcSignalingChannel(a);
+    const bobSig = new WebRtcSignalingChannel(b);
+    const factory = new MemoryRtcFactory();
+    const alice = new WebRtcConnectionManager({ factory, signaling: aliceSig });
+    const bob = new WebRtcConnectionManager({
+      factory,
+      signaling: bobSig,
+      receiver: {
+        async onChunk() {
+          return { lastSeq: 0 };
+        },
+        async onResumeQuery() {
+          return null;
+        },
+      },
+    });
+
+    // Both kick off at once.
+    const [aConn, bConn] = await Promise.all([
+      alice.getOrCreate('bob'),
+      bob.getOrCreate('alice'),
+    ]);
+
+    expect(aConn.state).toBe('connected');
+    expect(bConn.state).toBe('connected');
+    expect(alice.isConnected('bob')).toBe(true);
+    expect(bob.isConnected('alice')).toBe(true);
+
+    alice.destroy();
+    bob.destroy();
+  });
+});