style: apply nightly rustfmt import grouping across the workspace

rustfmt.toml sets group_imports, imports_granularity and imports_layout,
which are nightly-only; agents formatted with stable rustfmt, which
ignored them. This is a formatting-only pass with `cargo +nightly fmt`.

Test Plan:
- cargo clippy --workspace --all-targets -- -D warnings
- cargo test --workspace

crates/ghostty-termio/src/command.rs

@@ -14,7 +14,7 @@
 
 use std::{
     ffi::{CString, NulError, c_char},
-    os::fd::OwnedFd,
+    os::{fd::OwnedFd, unix::ffi::OsStrExt},
     panic::{AssertUnwindSafe, catch_unwind},
 };
 
@@ -24,7 +24,6 @@ use rustix::{
     process::{self, WaitOptions},
     stdio,
 };
-use std::os::unix::ffi::OsStrExt;
 
 /// Function executed /in the child process/ after the fork, but before
 /// exec'ing the command. If the function returns `Some(code)`, the child
@@ -609,11 +608,10 @@ mod tests {
     use std::{
         fs::File,
         io::{Read, Seek, SeekFrom},
+        os::fd::AsRawFd,
         sync::Arc,
     };
 
-    use std::os::fd::AsRawFd;
-
     use ghostty_os::TempDir;
 
     use super::*;