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/version.rs

@@ -2,8 +2,10 @@
 
 use std::io::{IsTerminal, Write};
 
-use crate::build_info::{self, BuildInfo};
-use crate::error::Error;
+use crate::{
+    build_info::{self, BuildInfo},
+    error::Error,
+};
 
 /// The `version` command is used to display information about Ghostty. Recognized as
 /// either `+version` or `--version`.