feat(testkit): deterministic fake platform ports + fixtures + replay oracle

Fakes for all 7 IiosPlatformPorts (deny/timeout/ambiguous controls), portal +
unknown-email fixtures, replayTwice idempotency oracle. Adds ingest request
contract. Vitest alias resolves workspace packages to source.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/iios-contracts/src/index.ts

@@ -1,5 +1,6 @@
 export * from './scope';
 export * from './enums';
+export * from './ingest';
 export * from './ports';
 export * from './events';
 export * from './commands';

packages/iios-contracts/src/ingest.ts

@@ -0,0 +1,42 @@
+import type { ScopeVector } from './scope';
+import type { HandleKind, InteractionKind, MessagePartKind } from './enums';
+
+/**
+ * The ingest API contract (Data Model §11 OpenAPI `IngestInteractionRequest`).
+ * A trusted host app or channel adapter posts this to `/v1/interactions/ingest`.
+ */
+export interface IngestInteractionRequest {
+  scope: ScopeVector;
+  channel: {
+    type: string; // PORTAL, EMAIL, WHATSAPP, ...
+    externalChannelId?: string;
+    capabilityContract?: Record<string, unknown>;
+  };
+  source: {
+    handleKind: HandleKind;
+    externalId: string;
+    displayName?: string;
+  };
+  kind?: InteractionKind;
+  thread?: {
+    externalThreadId?: string;
+    subject?: string;
+  };
+  parts: Array<{
+    kind: MessagePartKind;
+    bodyText?: string;
+    contentRef?: string;
+    mimeType?: string;
+  }>;
+  occurredAt: string;
+  providerEventId?: string;
+  metadata?: Record<string, unknown>;
+}
+
+export interface IngestInteractionResponse {
+  interactionId: string;
+  sourceHandleId: string;
+  threadId: string;
+  state: string;
+  next: string[];
+}