R console does not recognize the encoding of directly input text - r

Question

I have been wondering why the text that is directly typed in an R script does not seem to be treated as UTF-8 encoded? The file itself is saved and opened in UTF-8. For example, the encoding of Chinese text strings mixed with numbers is displayed as unknown according to the result in the console.
> str <- c("字符編碼問題", "字符編碼問題1", "字符編碼問題2")
> Encoding(str)
[1] "unknown" "unknown" "unknown"
Using the enc2utf8() function to declare the encoding changes the encoding recognized in R.
> str_utf <- enc2utf8(str)
> Encoding(str_utf)
[1] "UTF-8" "UTF-8" "UTF-8"
This issue is affecting the use of text processing function such as str_detect() because the text stored inside the txt_utf object is UTF-8 encoded whereas the text in the script has an unknown encoding. Declaring the encoding of every single search string is cumbersome. So my question is: How can the text in the script be recognized as UTF-8 by default?
> str_detect(str, "題[:digit:]")
[1] FALSE TRUE TRUE
# fails to detect text patterns in the UTF-8 object
> str_detect(str_utf, "題[:digit:]")
[1] FALSE FALSE FALSE
> str_detect(str_utf, enc2utf8("題[:digit:]"))
[1] FALSE TRUE TRUE
My R session information is as follows:
R version 4.1.1 (2021-08-10)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19042)
Matrix products: default
locale:
[1] LC_COLLATE=Chinese (Traditional)_Hong Kong SAR.950 LC_CTYPE=Chinese (Traditional)_Hong Kong SAR.950
[3] LC_MONETARY=Chinese (Traditional)_Hong Kong SAR.950 LC_NUMERIC=C
[5] LC_TIME=Chinese (Traditional)_Hong Kong SAR.950
system code page: 932