Rename to btest-rs, add LICENSE and README with full credits

- Rename package to btest-rs (Rust convention for reimplementations)
- MIT license matching the original btest-opensource license
- LICENSE explicitly credits Alex Samorukov's original work
- Comprehensive README with usage, performance numbers, and credits
- CLI --help references the original project

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/main.rs

@@ -12,10 +12,12 @@ use crate::protocol::*;
 #[derive(Parser, Debug)]
 #[command(
     name = "btest",
-    about = "MikroTik Bandwidth Test (btest) - server and client",
+    about = "btest-rs: MikroTik Bandwidth Test server & client in Rust",
     version,
-    long_about = "Compatible bandwidth testing tool for MikroTik RouterOS devices.\n\
-                  Supports TCP and UDP modes with optional authentication."
+    long_about = "btest-rs — A Rust reimplementation of the MikroTik Bandwidth Test protocol.\n\
+                  Compatible with MikroTik RouterOS devices. Supports TCP/UDP, bidirectional\n\
+                  testing, and MD5 authentication.\n\n\
+                  Based on btest-opensource by Alex Samorukov (https://github.com/samm-git/btest-opensource)"
 )]
 struct Cli {
     /// Run in server mode