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/marketplace.json

@@ -9,7 +9,7 @@
       "name": "beads",
       "source": "./",
       "description": "AI-supervised issue tracker for coding workflows",
-      "version": "0.45.0"
+      "version": "0.46.0"
     }
   ]
 }