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-testkit/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "@insignia/iios-testkit",
+  "version": "0.0.0",
+  "private": true,
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "files": ["dist"],
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "typecheck": "tsc -p tsconfig.json --noEmit"
+  },
+  "dependencies": {
+    "@insignia/iios-contracts": "workspace:*"
+  }
+}