feat(core-eslint): add no-undeclared-analytics-event ESLint rule

Adds the conformance/no-undeclared-analytics-event rule at warn severity,
mirroring no-undeclared-audit and no-undeclared-event-publish. The rule
cross-checks analytics.track("X", ...) literal slugs in *.use-case.ts
files against manifest.useCases[name].analyticsEvents, providing
sub-second editor feedback before boot-time conformance fires.

- Extends _manifest-ast.js to parse analyticsEvents arrays in both
  extractUseCaseEntry helpers
- Registers rule in plugin.js and base.js at ["warn", { repoRoot }]
- RuleTester fixtures: declared pass, undeclared warn, non-literal no-op,
  non-use-case file no-op, missing manifest entry no-op

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

packages/core-eslint/rules/_manifest-ast.test.js

@@ -36,9 +36,27 @@ describe("parseManifestUseCases", () => {
   jobs: [],
 } as const);`);
     expect(parseManifestUseCases(fp)).toEqual({
-      signIn: { mutates: false, audits: [], publishes: [], consumes: [] },
-      signUp: { mutates: true, audits: ["user.created"], publishes: ["auth.signed-up"], consumes: [] },
-      signOut: { mutates: true, audits: ["session.ended"], publishes: [], consumes: [] },
+      signIn: {
+        mutates: false,
+        audits: [],
+        publishes: [],
+        consumes: [],
+        analyticsEvents: [],
+      },
+      signUp: {
+        mutates: true,
+        audits: ["user.created"],
+        publishes: ["auth.signed-up"],
+        consumes: [],
+        analyticsEvents: [],
+      },
+      signOut: {
+        mutates: true,
+        audits: ["session.ended"],
+        publishes: [],
+        consumes: [],
+        analyticsEvents: [],
+      },
     });
   });
 
@@ -69,8 +87,20 @@ describe("parseManifestFully", () => {
       name: "auth",
       requiredCores: ["audit", "events"],
       useCases: {
-        signIn: { mutates: false, audits: [], publishes: [], consumes: [] },
-        signUp: { mutates: true, audits: ["user.created"], publishes: [], consumes: [] },
+        signIn: {
+          mutates: false,
+          audits: [],
+          publishes: [],
+          consumes: [],
+          analyticsEvents: [],
+        },
+        signUp: {
+          mutates: true,
+          audits: ["user.created"],
+          publishes: [],
+          consumes: [],
+          analyticsEvents: [],
+        },
       },
     });
   });