feat(core-eslint): add no-undeclared-consent-check rule (conformance gate 12)

Extends the conformance ESLint layer with the consent-check rule:

- `no-undeclared-consent-check` (warn): `consent.isGranted("X")` in a
  use-case file must match a category declared in `manifest.requiresConsent`;
  also warns when requiresConsent is declared but no isGranted call is found.
- `_manifest-ast.js`: adds `parseManifestFully` which extracts top-level
  `name`, `requiredCores`, `requiresConsent`, and per-use-case maps from the
  manifest AST; `requiresConsent` extraction tested in `_manifest-ast.test.js`.
- `_rule-context.js` / `_rule-schema.js`: shared helpers extracted from the
  existing per-rule files so the new rule can resolve use-case name + feature
  root without duplication.
- Existing rules (`no-undeclared-audit`, `no-undeclared-event-publish`,
  `no-undeclared-analytics-event`) updated to use the shared helpers.
- `plugin.js` + `base.js` register the rule at warn severity.
- CLAUDE.md + conformance-quickref.md: rule count advanced from 11 → 12.

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

packages/core-eslint/base.js

@@ -53,6 +53,7 @@ export default [
       "conformance/component-must-have-test": "warn",
       "conformance/atomic-tier-import-direction": "warn",
       "conformance/pii-declaration-must-be-complete": "warn",
+      "conformance/no-undeclared-consent-check": ["warn", { repoRoot }],
     },
   },
   {