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)

cmd/bd/info.go

@@ -296,6 +296,15 @@ type VersionChange struct {
 
 // versionChanges contains agent-actionable changes for recent versions
 var versionChanges = []VersionChange{
+	{
+		Version: "0.46.0",
+		Date:    "2026-01-06",
+		Changes: []string{
+			"NEW: Custom type support - Configure custom issue types in config.yaml (bd-649s)",
+			"NEW: Gas Town types extraction - Core Gas Town types in beads package (bd-i54l)",
+			"FIX: Gate workflow discovery - Better matching of GitHub Actions runs (bd-m8ew)",
+		},
+	},
 	{
 		Version: "0.45.0",
 		Date:    "2026-01-06",