chore: Bump version to 0.46.0

Updated all component versions:
- bd CLI: 0.45.0 → 0.46.0
- Plugin: 0.45.0 → 0.46.0
- MCP server: 0.45.0 → 0.46.0
- npm package: 0.45.0 → 0.46.0
- Documentation: 0.45.0 → 0.46.0

Changes in 0.46.0:
- Custom type support in beads config.yaml (bd-649s)
- Gas Town types extraction into beads core (bd-i54l)
- Gate workflow discovery improvements (bd-m8ew)

.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": "0.45.0",
+  "version": "0.46.0",
   "author": {
     "name": "Steve Yegge",
     "url": "https://github.com/steveyegge"