feat(core-events): scaffold events optional core

Scaffolded via pnpm turbo gen core-package events (generator-first,
ADR-022 pre-shipped zod trace landed in docs/library-decisions/).
Generator wired transpilePackages + E1/J eslint rule block. Two
story-00-precedent additions so the coverage gates pass: the
@vitest/coverage-v8 devDep (L0 sweep) and the honest symbols.ts
exclude (mirroring core-shared/vitest.config.ts) plus its missing
ALLOWED_GLOBS mirror in scripts/coverage/diff.mjs (L1 gate). No
consumers wired — compile-green floor for the walking-skeleton
PRD (ADR-027).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

packages/core-events/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "@repo/core-events",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "scripts": {
+    "build": "tsc --noEmit",
+    "lint": "eslint .",
+    "typecheck": "tsc --noEmit",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "@repo/core-shared": "workspace:*",
+    "zod": "^3.23.0"
+  },
+  "peerDependencies": {
+    "payload": "^3.0.0"
+  },
+  "peerDependenciesMeta": {
+    "payload": {
+      "optional": true
+    }
+  },
+  "devDependencies": {
+    "@repo/core-eslint": "workspace:*",
+    "@repo/core-testing": "workspace:*",
+    "@repo/core-typescript": "workspace:*",
+    "@vitest/coverage-v8": "^3.2.4",
+    "typescript": "^5.8.0",
+    "vitest": "^3.0.0"
+  }
+}