fix(rig): improve UX for rig creation (#7)

- Add progress feedback during slow clone operations (30+ seconds)
- Fix README Quick Start to match actual workflow (--git flag, crew add)
- Update install output to use 'gt mayor attach' consistently
- Clarify "Next steps" wording in rig add output

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

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

internal/cmd/rig.go

@@ -399,8 +399,8 @@ func runRigAdd(cmd *cobra.Command, args []string) error {
 	fmt.Printf("  └── polecats/\n")
 
 	fmt.Printf("\nNext steps:\n")
-	fmt.Printf("  gt crew add <name> --rig %s   # Create your workspace\n", name)
-	fmt.Printf("  cd %s/crew/<name>       # Work in your clone\n", filepath.Join(townRoot, name))
+	fmt.Printf("  gt crew add <name> --rig %s   # Create your personal workspace\n", name)
+	fmt.Printf("  cd %s/crew/<name>              # Start working\n", filepath.Join(townRoot, name))
 
 	return nil
 }