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-renderer/src/cursor.rs

@@ -84,10 +84,11 @@ pub fn style(state: &RenderState, opts: StyleOptions) -> Option<Style> {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use ghostty_terminal::terminal::{Options, ScrollViewport, Terminal};
     use ghostty_vt::modes::Mode;
 
+    use super::*;
+
     fn o(preedit: bool, focused: bool, blink_visible: bool) -> StyleOptions {
         StyleOptions {
             preedit,