fix: macOS bcopy conflict and Docker host binding

- Fix #11: Guard bcopy/bzero declarations with _VISUALCPP in commoninclude.h
  to avoid redefinition errors on macOS where <strings.h> provides them
- Fix #12: Add --host flag to serve command, default 127.0.0.1
  Docker now binds to 0.0.0.0 so Colima can reach the server from host
- Also fix truncate() panic when n < 3

main.go

@@ -116,6 +116,7 @@ Pipeline flags:
 
 Serve flags:
   -p, --port 0             HTTP port (0 = auto-assign)
+  --host 127.0.0.1         HTTP bind address (use 0.0.0.0 for Docker)
   --no-browser             don't open browser automatically`)
 }
 
@@ -596,6 +597,9 @@ func truncate(s string, n int) string {
 	if len(s) <= n {
 		return s
 	}
+	if n < 3 {
+		return s[:n]
+	}
 	return s[:n-3] + "..."
 }