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/rules/_manifest-ast.test.js

@@ -86,6 +86,7 @@ describe("parseManifestFully", () => {
     expect(parseManifestFully(fp)).toEqual({
       name: "auth",
       requiredCores: ["audit", "events"],
+      requiresConsent: [],
       useCases: {
         signIn: {
           mutates: false,
@@ -105,6 +106,23 @@ describe("parseManifestFully", () => {
     });
   });
 
+  it("extracts requiresConsent categories from the manifest", () => {
+    const fp = writeManifest(`export const consentManifest = defineFeature({
+  name: "consent",
+  requiredCores: [],
+  requiresConsent: ["analytics", "marketing"],
+  useCases: {},
+  realtimeChannels: [],
+  jobs: [],
+} as const);`);
+    expect(parseManifestFully(fp)).toEqual({
+      name: "consent",
+      requiredCores: [],
+      requiresConsent: ["analytics", "marketing"],
+      useCases: {},
+    });
+  });
+
   it("returns null when the manifest has no name", () => {
     const fp = writeManifest(`export const x = 1;`);
     expect(parseManifestFully(fp)).toBeNull();
@@ -124,6 +142,7 @@ export const realManifest = defineFeature({
     expect(parseManifestFully(fp)).toEqual({
       name: "real",
       requiredCores: [],
+      requiresConsent: [],
       useCases: {},
     });
   });