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/App/CardWindowHost.swift

@@ -213,7 +213,9 @@ final class CardWindowSession: CardSessionFlushing {
         // net effect, and the `comments/.trash/` purge, which must not run while a board step's undo
         // still restores comments out of it. Registering answers whether the step took the purge on —
         // and a board whose substrate keeps no steps has already run it by the time that answer comes
-        // back, which is how Pro keeps purging at the close flush without a word about tiers here.
+        // back, which is how a git board keeps purging at the close flush without a word about tiers
+        // here (and there is none to say since 12-editions.md ▸ PIVOT 2026-08-07 — the substrate is
+        // the board's mode, not a subscription).
         //
         // **This window stops owning its card's comment trash first** (ruled 2026-08-06 — the
         // open-window carve-out). While the window is open the store defers every purge of this
@@ -418,9 +420,11 @@ struct CardWindowHost: View {
     /// **This card's commit trail, or nothing at all** (05-card-window.md ▸ History).
     ///
     /// `nil` is the section's absence rule, read from the board's own git state rather than from a
-    /// flag: no `HistoryStore` means the free tier (12-editions.md — where the section never exists),
-    /// and a mode other than `git` means a board the app manages no history for. The object is held
-    /// by this host so it survives every snapshot, `thumbnails`' reason exactly.
+    /// flag: a mode other than `git` means a board the app manages no history for, on any tier. The
+    /// question stopped having a tier half at 12-editions.md ▸ PIVOT 2026-08-07 — every session
+    /// composes a git state now, so what decides the section is whether *this board's* history is
+    /// git-backed. The object is held by this host so it survives every snapshot, `thumbnails`'
+    /// reason exactly.
     private var cardHistory: CardHistory? {
         guard appModel.session(for: ref.board)?.gitMode == .git else { return nil }
         return history