Use BIP 78 spec terms in payjoin-cli prints

The CLI called the request to the receiver a "fallback request"
and the post-send tx info "Sent fallback transaction ...". The
request body is the Original PSBT in BIP 78 parlance, and the
fallback transaction is the signed original tx -- which we have
not sent at that point, only computed. Tighten the wording to
match the spec.

Also rename "Posted original proposal..." to "Posted Original
PSBT..." for the v2 sender path. The internal name "Original
Proposal" stays in BIP 77 (Original PSBT plus extra params); only
the user-facing print is changed.

Author: DanGould

payjoin-cli/src/app/v1.rs

@@ -70,7 +70,7 @@ impl AppTrait for App {
             .create_v1_post_request();
         let http = http_agent(&self.config)?;
         let body = String::from_utf8(req.body.clone()).unwrap();
-        println!("Sending fallback request to {}", req.url);
+        println!("Sending Original PSBT to {}", req.url);
         let response = http
             .post(req.url)
             .header("Content-Type", req.content_type)
@@ -81,9 +81,9 @@ impl AppTrait for App {
         let fallback_tx = Psbt::from_str(&body)
             .map_err(|e| anyhow!("Failed to load PSBT from base64: {}", e))?
             .extract_tx()?;
-        println!("Sent fallback transaction txid: {}", fallback_tx.compute_txid());
+        println!("Fallback transaction txid: {}", fallback_tx.compute_txid());
         println!(
-            "Sent fallback transaction hex: {:#}",
+            "Fallback transaction hex: {:#}",
             payjoin::bitcoin::consensus::encode::serialize_hex(&fallback_tx)
         );
         let psbt = ctx.process_response(&response.bytes().await?).map_err(|e| {

payjoin-cli/src/app/v2/mod.rs

@@ -180,7 +180,7 @@ impl AppTrait for App {
                 .create_v1_post_request();
                 let http = http_agent(&self.config)?;
                 let body = String::from_utf8(req.body.clone()).unwrap();
-                println!("Sending fallback request to {}", req.url);
+                println!("Sending Original PSBT to {}", req.url);
                 let response = http
                     .post(req.url)
                     .header("Content-Type", req.content_type)
@@ -191,9 +191,9 @@ impl AppTrait for App {
                 let fallback_tx = payjoin::bitcoin::Psbt::from_str(&body)
                     .map_err(|e| anyhow!("Failed to load PSBT from base64: {}", e))?
                     .extract_tx()?;
-                println!("Sent fallback transaction txid: {}", fallback_tx.compute_txid());
+                println!("Fallback transaction txid: {}", fallback_tx.compute_txid());
                 println!(
-                    "Sent fallback transaction hex: {:#}",
+                    "Fallback transaction hex: {:#}",
                     payjoin::bitcoin::consensus::encode::serialize_hex(&fallback_tx)
                 );
                 let psbt = ctx.process_response(&response.bytes().await?).map_err(|e| {
@@ -504,7 +504,7 @@ impl App {
         )?;
         let response = self.post_request(req).await?;
         let sender = sender.process_response(&response.bytes().await?, ctx).save(persister)?;
-        println!("Posted original proposal...");
+        println!("Posted Original PSBT...");
         self.get_proposed_payjoin_psbt(sender, persister).await
     }