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>

Cargo.toml

@@ -1,12 +1,15 @@
 [package]
-name = "mikrotik-btest"
+name = "btest-rs"
 version = "0.1.0"
 edition = "2021"
-description = "MikroTik Bandwidth Test (btest) server and client implementation in Rust"
+description = "MikroTik Bandwidth Test (btest) server and client — a Rust reimplementation"
 license = "MIT"
+repository = "https://github.com/samm-git/btest-opensource"
+keywords = ["mikrotik", "bandwidth", "btest", "network", "benchmarking"]
+categories = ["command-line-utilities", "network-programming"]
 
 [lib]
-name = "mikrotik_btest"
+name = "btest_rs"
 path = "src/lib.rs"
 
 [[bin]]