chore: Bump version to 0.15.0

Updated all component versions:
- bd CLI: 0.14.0 → 0.15.0
- Plugin: 0.14.0 → 0.15.0
- MCP server: 0.14.0 → 0.15.0
- Documentation: 0.14.0 → 0.15.0

Generated by scripts/bump-version.sh

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "beads",
   "description": "AI-supervised issue tracker for coding workflows. Manage tasks, discover work, and maintain context with simple CLI commands.",
-  "version": "0.14.0",
+  "version": "0.15.0",
   "author": {
     "name": "Steve Yegge",
     "url": "https://github.com/steveyegge"