feat(core-consent): add ConsentProvider + useConsent() React subpath

Adds the ./react subpath to @repo/core-consent following the same
pattern as @repo/core-analytics/react:

- ConsentProvider wraps IConsent in React context
- useConsent() returns the injected IConsent or throws ConsentContextError
- RTL tests cover context propagation, grant/withdraw delegation,
  isGranted state reflection, getCategories, and missing-provider error
- package.json: ./react export + React optional peerDep + RTL devDeps
- tsconfig: extend react-library.json, include .tsx
- vitest.config: jsdom environment for .test.tsx + jsdom setup

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

packages/core-consent/package.json

@@ -5,7 +5,8 @@
   "type": "module",
   "exports": {
     ".": "./src/index.ts",
-    "./di": "./src/di/bind-production.ts"
+    "./di": "./src/di/bind-production.ts",
+    "./react": "./src/react/index.ts"
   },
   "scripts": {
     "build": "tsc --noEmit",
@@ -19,19 +20,27 @@
     "zod": "^3.24.0"
   },
   "peerDependencies": {
-    "payload": "^3.0.0"
+    "payload": "^3.0.0",
+    "react": "^18.0.0 || ^19.0.0"
   },
   "peerDependenciesMeta": {
     "payload": {
       "optional": true
+    },
+    "react": {
+      "optional": true
     }
   },
   "devDependencies": {
     "@repo/core-eslint": "workspace:*",
     "@repo/core-testing": "workspace:*",
     "@repo/core-typescript": "workspace:*",
+    "@testing-library/react": "^16.0.0",
+    "@types/react": "^19.0.0",
     "@vitest/coverage-v8": "^3.0.0",
+    "jsdom": "^25.0.0",
     "payload": "^3.14.0",
+    "react": "^19.0.0",
     "typescript": "^5.8.0",
     "vitest": "^3.0.0"
   }