catch link names that are too long earlier

There is a limit of 32 characters for link names. We find this out the hard way currently.

ry@masaka:~/scratch/softnpu-uart-issue$ RUST_BACKTRACE=1 pfexec ./target/debug/softnpu-uart-issue launc
thread 'main' panicked at /home/ry/.cargo/git/checkouts/netadm-sys-25ac2db9b1b244c6/59e69ef/libnet/src/link.rs:485:9:
index out of bounds: the len is 32 but the index is 32
stack backtrace:
Nov 25 19:53:35.632 INFO creating links
   0: rust_begin_unwind
             at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:595:5
   1: core::panicking::panic_fmt
             at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:67:14
   2: core::panicking::panic_bounds_check
             at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:162:5
   3: libnet::link::linkname_to_id
             at /home/ry/.cargo/git/checkouts/netadm-sys-25ac2db9b1b244c6/59e69ef/libnet/src/link.rs:485:9
   4: libnet::linkname_to_id
             at /home/ry/.cargo/git/checkouts/netadm-sys-25ac2db9b1b244c6/59e69ef/libnet/src/lib.rs:226:5
   5: libnet::LinkHandle::id
             at /home/ry/.cargo/git/checkouts/netadm-sys-25ac2db9b1b244c6/59e69ef/libnet/src/lib.rs:198:39
   6: libnet::delete_link
             at /home/ry/.cargo/git/checkouts/netadm-sys-25ac2db9b1b244c6/59e69ef/libnet/src/lib.rs:318:20
   7: libfalcon::Link::create::{{closure}}
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/lib.rs:1009:17
   8: libfalcon::libnet_retry
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/lib.rs:1230:12
   9: libfalcon::Link::create
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/lib.rs:1008:13
  10: libfalcon::Runner::net_launch::{{closure}}
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/lib.rs:472:13
  11: libfalcon::Runner::do_launch::{{closure}}
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/lib.rs:484:27
  12: libfalcon::Runner::launch::{{closure}}
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/lib.rs:435:32
  13: libfalcon::cli::launch::{{closure}}
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/cli.rs:310:32
  14: libfalcon::cli::run::{{closure}}
             at /home/ry/.cargo/git/checkouts/falcon-c754111a71d466df/9de4129/lib/src/cli.rs:182:23
  15: softnpu_uart_issue::main::{{closure}}
             at ./src/main.rs:15:17
  16: tokio::runtime::park::CachedParkThread::block_on::{{closure}}
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/park.rs:282:63
  17: tokio::runtime::coop::with_budget
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/coop.rs:107:5
  18: tokio::runtime::coop::budget
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/coop.rs:73:5
  19: tokio::runtime::park::CachedParkThread::block_on
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/park.rs:282:31
  20: tokio::runtime::context::blocking::BlockingRegionGuard::block_on
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/context/blocking.rs:66:9
  21: tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}}
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/scheduler/multi_thread/mod.rs:87:13
  22: tokio::runtime::context::runtime::enter_runtime
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/context/runtime.rs:65:16
  23: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/scheduler/multi_thread/mod.rs:86:9
  24: tokio::runtime::runtime::Runtime::block_on
             at /home/ry/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.34.0/src/runtime/runtime.rs:350:45
  25: softnpu_uart_issue::main
             at ./src/main.rs:17:5
  26: core::ops::function::FnOnce::call_once
             at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Reproduce the panic with the documented softnpu-uart-issue launch command and inspect libnet/src/link.rs around linkname_to_id line 485, then trace the caller through libfalcon's Link::create at lib/src/lib.rs:1008. Done means a link name exceeding the 32-character limit is caught before the current index-out-of-bounds panic; add or update a regression test if the repository provides one.