Add BodyRaw() method to retrieve raw article body without decoding

[asdffer]

Add BodyRaw() method to retrieve raw article body without decoding

Description

Adds a new BodyRaw() method to the Client API that retrieves article bodies without applying yEnc or UU decoding. This is useful for cases where the raw encoded content needs to be inspected or processed directly without automatic decoding.

Changes

• New public method BodyRaw(): Retrieves raw article body bytes without decoding
• RawMode flag: Added to Request and NNTPResponse structs to skip the decoding pipeline
• Updated decoder: Modified the decode() function to pass through raw bytes when RawMode is enabled, while still handling NNTP protocol details like dot-stuffing

Implementation Details

• When RawMode=true, the decoder skips yEnc and UU decoding logic entirely
• Raw bytes are streamed directly to the response buffer
• NNTP protocol handling (end markers, dot-stuffing) is preserved
• Integrates seamlessly with existing provider retry logic via sendRaw() helper

Usage Example

body, err := client.BodyRaw(ctx, messageID)
if err != nil {
    log.Fatal(err)
}
// body.Bytes contains raw, undecoded article content

Testing

• No breaking changes to existing API
• Existing Body/BodyStream/BodyAsync methods unchanged
• RawMode is opt-in via the new BodyRaw() method

[javi11]

Can you instead just reuse everything that is there just add the new method and pass a variable to prevent the yenc decoder?