feat(core-consent): scaffold package with types, IConsent, withConsent brand wrapper

- Add packages/core-consent with ConsentCategory, ConsentState,
  UserConsentState types and IConsent interface
- Add withConsent wrapper attaching __consentChecked brand at bind time;
  unit tests assert brand attachment and factory passthrough
- Add ConsentChecked<F> type to core-shared/conformance/brands.ts and
  isConsentChecked helper to brand-runtime.ts
- Extend FeatureManifest with requiresConsent?: readonly string[] field
- Extend assertFeatureConformance to require __consentChecked brand when
  requiresConsent.length > 0; synthetic fixture tests cover pass/fail cases
- Propagate __consentChecked in withSpan PROPAGATED_BRANDS so the outermost
  binding carries the brand

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

packages/core-consent/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "@repo/core-consent",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "scripts": {
+    "build": "tsc --noEmit",
+    "lint": "eslint .",
+    "typecheck": "tsc --noEmit",
+    "test": "vitest run --passWithNoTests"
+  },
+  "dependencies": {
+    "@repo/core-shared": "workspace:*"
+  },
+  "devDependencies": {
+    "@repo/core-eslint": "workspace:*",
+    "@repo/core-testing": "workspace:*",
+    "@repo/core-typescript": "workspace:*",
+    "@vitest/coverage-v8": "^3.0.0",
+    "typescript": "^5.8.0",
+    "vitest": "^3.0.0"
+  }
+}