refactor: simplify plugin dependency handling

Simplify plugin installation and runtime loading around package-manager-owned dependencies, with Jiti reserved for local/TS fallback paths.

Also scans npm plugin install roots so hoisted transitive dependencies are covered by dependency denylist and node_modules symlink checks.

extensions/memory-core/openclaw.plugin.json

@@ -7,9 +7,6 @@
   "contracts": {
     "memoryEmbeddingProviders": ["local"]
   },
-  "runtimeDependencies": {
-    "localMemoryEmbedding": ["node-llama-cpp@3.18.1"]
-  },
   "commandAliases": [
     {
       "name": "dreaming",