chore(release): bump version to 0.15.0

- Updated `VERSION` in `version.ts` to `0.15.0`.
- Updated `npm` badge in `README.md` to reflect version `0.15.0`.
- Updated `version` field and dependency reference in `cli-package/package.json` to `0.15.0`.

**Purpose**: Prepare for release by synchronizing version across source files, documentation, and package dependencies.

cli-package/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@soulcraft/brainy-cli",
-  "version": "0.14.0",
+  "version": "0.15.0",
   "description": "Command-line interface for the Brainy vector graph database",
   "type": "module",
   "bin": {
@@ -40,7 +40,7 @@
     "url": "git+https://github.com/soulcraft-research/brainy.git"
   },
   "dependencies": {
-    "@soulcraft/brainy": "0.14.0",
+    "@soulcraft/brainy": "0.15.0",
     "commander": "^14.0.0",
     "omelette": "^0.4.17"
   },