The tier axis comes out of the git stack — compose unconditional, postures mode-driven

HistoryStore.compose(boardRoot📒) returns non-optional and runs for
every session — the nil the gate produced was the only nil it ever had.
makeHistoryProvider is a one-axis decision: git-mode boards bind the git
provider, everything else native, in every tier; Session.tier stays
recorded, dormant. BoardGitSection shrinks to the four mode postures
(.absent and .proPointer die, BoardGitNote and the .git probe with them);
every board carries all three popover tabs (BoardInfoTab.available
retired); the titlebar branch shows on any git-mode board; the settings
sheet and card History section stop reading tier. InertGitTests is
repurposed as UntouchedGitTests — the file layer still never opens .git,
now load-bearing for mode-none boards. The accessibility audit reaches the
settings sheet at last: the fixture board hosts it in every tier, so the
free-fixture disabled-row test becomes an open-and-audit test.

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

Kanban/History/HistoryProviding.swift

@@ -262,21 +262,25 @@ public struct HistoryStep {
 /// seam from a window is the one coarse step its close registers.
 ///
 /// `AppModel.BoardSession` is where the board half's ownership lives, and the composition root binds
-/// which implementation it gets — **following the board, not the tier alone** (re-ruled 2026-07-31):
-/// a board without app-managed git — repo-nested included (re-ruled 2026-07-31) — binds
-/// `NativeHistoryProvider` (two step stacks over the inverses registered at the Writer boundary) in
-/// every tier, a Pro git board binds the git provider (undo as forward restore commits over HEAD's
-/// first-parent ancestry — 06-history-undo.md), and Teams inherits Pro's.
+/// which implementation it gets — **following the board, and since the 2026-08-07 pivot the board
+/// alone** (re-ruled 2026-07-31; 12-editions.md ▸ PIVOT 2026-08-07): a board without app-managed git
+/// — repo-nested included (re-ruled 2026-07-31) — binds `NativeHistoryProvider` (two step stacks over
+/// the inverses registered at the Writer boundary), and a git-mode board binds the git provider (undo
+/// as forward restore commits over HEAD's first-parent ancestry — 06-history-undo.md). Both answers
+/// are the same in every tier; the tier used to decide whether git was on the table at all, and no
+/// longer does.
 ///
 /// ### What this protocol deliberately does not say
 ///
 /// - **No `NSUndoManager`, anywhere in the signature.** It is the native provider's implementation
 ///   detail, and a seam that vended one would be a seam only one provider could ever satisfy — the
 ///   opposite of the reason the seam exists at all ("the free tier's native undo is the first proof
-///   the seam is real", 12). AppKit still needs an `UndoManager` to hand the responder chain; that
-///   adapter is `BoardUndoManager`, which sits *over* this protocol rather than inside it.
-/// - **No persistence promise.** The native stack dies with the session (13); Pro's survives
-///   relaunch because git does (06). Both are honest implementations of these seven members.
+///   the seam is real", 12 — written when native undo was the free tier's; the proof it names is
+///   two working substrates, which the pivot leaves standing). AppKit still needs an `UndoManager`
+///   to hand the responder chain; that adapter is `BoardUndoManager`, which sits *over* this
+///   protocol rather than inside it.
+/// - **No persistence promise.** The native stack dies with the session (13); the git provider's
+///   survives relaunch because git does (06). Both are honest implementations of these seven members.
 /// - **No routing.** Which surface ⌘Z reaches is focus's answer, not the substrate's
 ///   (06 ▸ Undo routing, tier-independent) — `BoardUndoRouting`.
 ///