feat(memory): add memory extension with core functionality and tests

- Implemented MemoryStore class for managing concepts with YAML frontmatter.
- Added methods for creating, reading, updating, and deleting concepts.
- Introduced locking mechanism for concurrent access.
- Developed search and hinting capabilities for concept retrieval.
- Created tests for access control and store functionality.
- Added long-term memory skill documentation and operational guidelines.
- Included package.json and package-lock.json for dependency management.

extensions/memory/package-lock.json

@@ -0,0 +1,28 @@
+{
+  "name": "kimiko-memory-extension",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "kimiko-memory-extension",
+      "dependencies": {
+        "yaml": "^2.8.1"
+      }
+    },
+    "node_modules/yaml": {
+      "version": "2.9.0",
+      "resolved": "https://registry.npmjs.org/yaml/-/yaml-2.9.0.tgz",
+      "integrity": "sha512-2AvhNX3mb8zd6Zy7INTtSpl1F15HW6Wnqj0srWlkKLcpYl/gMIMJiyuGq2KeI2YFxUPjdlB+3Lc10seMLtL4cA==",
+      "license": "ISC",
+      "bin": {
+        "yaml": "bin.mjs"
+      },
+      "engines": {
+        "node": ">= 14.6"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/eemeli"
+      }
+    }
+  }
+}