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-cli/src/new_window.rs

@@ -237,9 +237,10 @@ pub fn run(args: &[String]) -> Result<u8, Error> {
 #[cfg(test)]
 mod tests {
     #![allow(clippy::unwrap_used)]
-    use super::*;
     use ghostty_config::cli_args::{VecIterator, parse};
 
+    use super::*;
+
     fn parse_str(s: &str) -> Options {
         let mut opts = Options::default();
         let mut it = VecIterator::from_str_args(s);