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-build-data/src/zsh.rs

@@ -4,8 +4,13 @@ use std::fmt::Write as _;
 
 use ghostty_config::cli_args::FieldKind;
 
-use crate::chunks_zsh::{C0, C1, C2, C3};
-use crate::{actions, config_fields, join_names, join_packed};
+use crate::{
+    actions,
+    chunks_zsh::{C0, C1, C2, C3},
+    config_fields,
+    join_names,
+    join_packed,
+};
 
 const EQUALS_REQUIRED: &str = "=-:::";