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/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "@repo/core-typescript/base.json",
+  "extends": "@repo/core-typescript/react-library.json",
   "compilerOptions": {
     "outDir": "dist",
     "rootDir": ".",
@@ -7,6 +7,6 @@
       "@/*": ["./src/*"]
     }
   },
-  "include": ["**/*.ts"],
+  "include": ["**/*.ts", "**/*.tsx"],
   "exclude": ["node_modules", "dist"]
 }