chore: pre-publish metadata and .npmignore

- keywords: [ai, agents, guardrails, runtime, budget, limits]
- homepage: no #readme suffix
- .npmignore: excludes src, examples, docs, .github, tsconfig, tests

Author: repoforge-dev

packages/core/.npmignore

@@ -0,0 +1,6 @@
+src
+examples
+docs
+.github
+tsconfig.json
+*.test.ts

packages/core/package.json

@@ -22,18 +22,16 @@
   "keywords": [
     "ai",
     "agents",
-    "enforcement",
+    "guardrails",
+    "runtime",
     "budget",
-    "rate-limit",
-    "safety",
-    "autonomous-agents",
-    "llm"
+    "limits"
   ],
   "repository": {
     "type": "git",
     "url": "https://github.com/032383justin/authority-layer"
   },
-  "homepage": "https://github.com/032383justin/authority-layer#readme",
+  "homepage": "https://github.com/032383justin/authority-layer",
   "bugs": {
     "url": "https://github.com/032383justin/authority-layer/issues"
   },