feat(core-consent): add PayloadConsent, RecordingConsent and DI binders

Implements the Payload-backed IConsent that reads/writes users.consentState
and emits CONSENT_GRANT/CONSENT_WITHDRAW audit entries via injected auditLog.
Adds RecordingConsent test double in core-testing for unit-test injection.
Adds bindProductionConsent/bindDevSeedConsent DI binders and InMemoryConsent
for dev/seed contexts. Contract tests cover grant/withdraw/isGranted round-trip,
audit entry shape, metadata persistence (bannerVersion/policyVersion/method),
and getCategories reflection of state.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-consent/package.json

@@ -4,7 +4,8 @@
   "private": true,
   "type": "module",
   "exports": {
-    ".": "./src/index.ts"
+    ".": "./src/index.ts",
+    "./di": "./src/di/bind-production.ts"
   },
   "scripts": {
     "build": "tsc --noEmit",
@@ -15,11 +16,20 @@
   "dependencies": {
     "@repo/core-shared": "workspace:*"
   },
+  "peerDependencies": {
+    "payload": "^3.0.0"
+  },
+  "peerDependenciesMeta": {
+    "payload": {
+      "optional": true
+    }
+  },
   "devDependencies": {
     "@repo/core-eslint": "workspace:*",
     "@repo/core-testing": "workspace:*",
     "@repo/core-typescript": "workspace:*",
     "@vitest/coverage-v8": "^3.0.0",
+    "payload": "^3.14.0",
     "typescript": "^5.8.0",
     "vitest": "^3.0.0"
   }