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-inspector/src/widgets/pagelist.rs

@@ -1,12 +1,20 @@
 //! PageList inspector (ZIG/src/inspector/widgets/pagelist.zig).
 
 use dear_imgui_rs::{
-    ComboBoxHeight, ComboBoxOptions, ItemHoveredFlags, MouseButton, StyleColor, TableFlags,
-    TreeNodeFlags, Ui,
+    ComboBoxHeight,
+    ComboBoxOptions,
+    ItemHoveredFlags,
+    MouseButton,
+    StyleColor,
+    TableFlags,
+    TreeNodeFlags,
+    Ui,
+};
+use ghostty_terminal::{
+    page_list::{PageList, Scroll, Scrollbar},
+    point::{Coordinate, Point, Tag},
+    style::DEFAULT_ID,
 };
-use ghostty_terminal::page_list::{PageList, Scroll, Scrollbar};
-use ghostty_terminal::point::{Coordinate, Point, Tag};
-use ghostty_terminal::style::DEFAULT_ID;
 
 use super::{help_marker, page, style};
 use crate::units::to_kibi_bytes;