feat(types): add rig identity bead type (gt-zmznh)

- Add TypeRig constant to IssueType enum
- Update IsValid() method to include TypeRig
- Add UI color (orange) and style for rig type
- Update CLI flag descriptions in create and update commands
- Add Obsidian export tag for rig type
- Add comprehensive test cases for rig and other newer types

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/validation/bead_test.go

@@ -128,6 +128,7 @@ func TestParseIssueType(t *testing.T) {
 		{"gate type", "gate", types.TypeGate, false, ""},
 		{"agent type", "agent", types.TypeAgent, false, ""},
 		{"role type", "role", types.TypeRole, false, ""},
+		{"rig type", "rig", types.TypeRig, false, ""},
 		{"message type", "message", types.TypeMessage, false, ""},
 
 		// Case sensitivity (function is case-sensitive)