Search takes the center — the titlebar placement grammar ratified

Redesign card 6d5a97fd resolved off the 2026-08-01 live try-out: leading is
board identity, center is view controls, trailing stays the user's catalog.
centeredItemIdentifiers, not a flexible-space sandwich — centers against the
window, holds as catalog items install, reaches machines with a saved
arrangement; defaultItems and its pinned tests untouched. 03 records the
grammar and the accepted tensions (widget-vs-field budget in narrow windows,
HIG's trailing convention yielding).

Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy

Kanban/UI/Board/BoardToolbar.swift

@@ -138,6 +138,11 @@ enum BoardToolbar {
             specs: specs(store: store, search: search),
             defaults: defaultItems
         )
+        // Centered against the window, not a flexible-space sandwich (03 ▸ Toolbar's placement
+        // grammar, ratified 2026-08-06): `centeredItemIdentifiers` holds as catalog items install
+        // and sits outside the autosaved configuration, so it reaches machines that saved an
+        // arrangement under the old trailing default. `defaultItems` is untouched.
+        controller.toolbar.centeredItemIdentifiers = [.boardSearch]
         controller.onInstalledItemsChanged = { [weak search] identifiers in
             search?.isInstalledInToolbar = identifiers.contains(.boardSearch)
         }