docs: the arrange pass's notes name things that were renamed under them

`maximized_transition` became `tiled_transition` when the mode it steps
was renamed `Maximized` → `Tiled`, but the doc kept the old name in both
places it appears — the list of per-section placement functions and the
bullet explaining the step. The other four names in that list are still
right. The note now points at the rename so the old name stays findable.

Two enum lists had also fallen behind their enums. `WindowClass` grew
`Grid`, the world-anchored grid client; `TilingMode` grew `Utility`,
which matters more than a missing name usually would — it is `Status`
minus the docking, it is never inferred from a sizing hint, and a
client only gets it by asking for it through `set_utility`. A reader
working from the old list would have had no reason to think either
existed.

Co-Authored-By: Claude Opus 5 <[email protected]>

 CLAUDE.md | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/CLAUDE.md b/CLAUDE.md
index b8428bd..51fd8ac 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -71,13 +71,16 @@ Key conventions inside the pass:
   with multiple outputs the final plan reflects the last one (mirroring the
   mechanism loop it replaced).
 - `classify_window()` maps each window to a `WindowClass`
-  (`Background`/`StatusBar`/`Hidden`/`Overlay`/`Normal`); an Overlay window
-  mid-drag arranges as Normal.
+  (`Background`/`StatusBar`/`Grid`/`Hidden`/`Overlay`/`Normal`); an Overlay
+  window mid-drag arranges as Normal, and `Grid` is the world-anchored grid
+  client, placed at its patch's virtual origin with scale `zoom / patch.scale`.
 - Placement is composed from per-section pure functions — `compute_usable_area`,
   `place_overlay_window`, `place_normal_window`, `layout_status_bars`,
-  `maximized_transition` — each individually callable and tested.
-- `maximized_transition()` is a state-machine step (Enter saves restore geometry,
-  Exit restores it); the saved state itself lives on the mechanism side.
+  `tiled_transition` — each individually callable and tested.
+- `tiled_transition()` is a state-machine step (Enter saves restore geometry,
+  Exit restores it); the saved state itself lives on the mechanism side. It was
+  `maximized_transition` until the mode it steps was renamed `Maximized` →
+  `Tiled` (see `tiling.rs` below).
 
 ### The `Policy` / `Compositor` trait boundary (`api.rs` + `actions.rs`)
 
@@ -186,9 +189,13 @@ The crate owns what a binding *means*; the compositor owns the physical half
 - `tiling.rs` — `TilingMode` enum: a window is `Floating` or `Tiled` (all
   content edges on visible desktop-grid cell edges; tiled windows report the
   xdg maximized state), plus `Fullscreen` and the internal `Popup` /
-  `Overlay` / `Status` roles. Serialized into saved state — serde aliases
-  map the retired names (`Cascade`/`Grid` → `Floating`, `Maximized` →
-  `Tiled`); keep aliases when renaming variants.
+  `Overlay` / `Status` / `Utility` roles. `Utility` is `Status` minus the
+  docking: a tool window whose shape its own contents decide, floating and
+  movable like any window but offered no resize affordance and given no saved
+  geometry. It is never inferred from a sizing hint — only the client declares
+  it, via `set_utility` on the cce window-management protocol. Serialized into
+  saved state — serde aliases map the retired names (`Cascade`/`Grid` →
+  `Floating`, `Maximized` → `Tiled`); keep aliases when renaming variants.
 - `overview.rs` — overview-mode move rules: `displace` relocates windows a
   drag covers (past an overlap threshold) to the side the drag vacated,
   called by the mechanism on every motion event of an overview move.