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/shaper/run.rs

@@ -12,12 +12,17 @@
 use std::hash::{DefaultHasher, Hash, Hasher};
 
 use ghostty_config::types_a::FontShapingBreak;
-use ghostty_terminal::page::{Cell, ContentTag, Page, Wide};
-use ghostty_terminal::style::{Color, Style as TermStyle};
+use ghostty_terminal::{
+    page::{Cell, ContentTag, Page, Wide},
+    style::{Color, Style as TermStyle},
+};
 
-use crate::collection::Index;
-use crate::shared_grid::{Error as GridError, SharedGrid};
-use crate::{Presentation, Style};
+use crate::{
+    Presentation,
+    Style,
+    collection::Index,
+    shared_grid::{Error as GridError, SharedGrid},
+};
 
 /// The Kitty graphics unicode placeholder codepoint
 /// (`terminal.kitty.graphics.unicode.placeholder`).