feat(core-consent): extend generator with consent template + fix withCapture brand propagation

- Add consent to CORE_PACKAGE_GENERATORS in turbo/generators/config.ts so
  pnpm turbo gen core-package consent is a valid command (not hand-rollable)
- Create turbo/generators/templates/core-package/consent/ mirroring the
  analytics template shape (AGENTS.md, package.json, tsconfig, turbo, vitest,
  eslint, src/index.ts scaffolds)
- Regenerate packages/core-consent/ from the new template (replaces the
  previous hand-rolled attempt that violated the generator-first rule)
- Add __consentChecked to withCapture PROPAGATED_BRANDS so the brand bubbles
  through the full withSpan→withCapture wrapper chain to the outermost binding
  that assertFeatureConformance reads

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

coverage/summary.json

@@ -1,6 +1,6 @@
 {
-  "generatedAt": "2026-05-19T10:39:50.009Z",
-  "commit": "f5d08dc",
+  "generatedAt": "2026-05-19T11:00:08.934Z",
+  "commit": "9cb2fa3",
   "repo": {
     "statements": 96.5,
     "branches": 91.82,