refactor: the hub is neshub everywhere

Six comments across nescope, neswire and nescapture still named
nestri-guest-hub, plus one still naming nestri-protocol. Deferred from the
import commits so the rename would read as one change rather than six
unexplained edits inside otherwise-verbatim trees.

Comments only. Realigned an ASCII box in encode.rs that the shorter name
knocked crooked.

apps/neswire/src/main.rs

@@ -5,7 +5,7 @@ use clap::Parser;
 
 #[derive(Parser, Debug)]
 struct Args {
-    /// Path for the audio IPC socket (neswire → nestri-guest-hub)
+    /// Path for the audio IPC socket (neswire → neshub)
     #[arg(
         long,
         env = "NESWIRE_IPC_PATH",