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-font/src/codepoint_map.rs

@@ -7,13 +7,13 @@
 //! The canonical definition lives in `ghostty-config` (the `font-codepoint-map`
 //! option parses straight into it); it is re-exported here.
 
-pub use ghostty_config::font_types::CodepointMap;
-pub use ghostty_config::font_types::CodepointMapEntry as Entry;
+pub use ghostty_config::font_types::{CodepointMap, CodepointMapEntry as Entry};
 #[cfg(test)]
 mod tests {
-    use super::*;
     use ghostty_config::font_types::Descriptor;
 
+    use super::*;
+
     fn desc(family: &str) -> Descriptor {
         Descriptor {
             family: Some(family.to_string()),