refactor(purchases): drop the blind-mode disclaimer modal

Purchases is now exercised against an account with real purchases, so
the one-time "built in blind mode" notice no longer describes the
feature. Remove the modal, its controller state, the bridge invokable,
the persisted pref and the three strings from the seven catalogs that
carried them.

cc

crates/qbz-qt/qml/views/PurchasesView.qml

@@ -557,88 +557,4 @@ Rectangle {
         anchors.bottom: parent.bottom
         target: flick
     }
-
-    // ── One-time disclaimer modal (QoL round) ────────────────────────────
-    // The WindowsDisclaimerModal mechanism on the purchases pref seam:
-    // seeded from `purchases_disclaimer_seen` on entry, OK persists it and
-    // it never returns. Overlay shape + wheel-lock are the
-    // DiscoverConfigModal pattern (plain Item, not a Popup — each surface
-    // eats its own wheel; ADR-009 z ≥ 3000). The scrim does NOT dismiss:
-    // like the Windows disclaimer, the only way out is the button, so a
-    // stray click cannot silently acknowledge it forever.
-    Item {
-        visible: root.doc.disclaimerVisible === true
-        enabled: visible
-        anchors.fill: parent
-        z: 3100
-
-        Rectangle {
-            anchors.fill: parent
-            radius: theme.radiusMd
-            color: "#bf000000"
-            MouseArea {
-                anchors.fill: parent
-                onClicked: {}
-                onWheel: function (wheel) { wheel.accepted = true }
-            }
-        }
-
-        Rectangle {
-            width: Math.min(parent.width - 80, 520)
-            height: Math.min(discCol.implicitHeight + 48, parent.height - 80)
-            x: Math.round((parent.width - width) / 2)
-            y: Math.round((parent.height - height) / 2)
-            radius: theme.radiusMd
-            color: theme.surfaceCard
-            border.width: 1
-            border.color: theme.borderSubtle
-            clip: true
-
-            MouseArea {
-                anchors.fill: parent
-                onWheel: function (wheel) { wheel.accepted = true }
-            }
-
-            Column {
-                id: discCol
-                x: 24
-                y: 24
-                width: parent.width - 48
-                spacing: 14
-
-                Text {
-                    width: parent.width
-                    text: QbzSession.tr("About music purchases", QbzSession.trRev)
-                    color: theme.textPrimary
-                    font.pixelSize: 17
-                    font.weight: Font.DemiBold
-                    wrapMode: Text.WordWrap
-                }
-                Text {
-                    width: parent.width
-                    text: QbzSession.tr("Music purchases are not available in every country or region where the platform offers streaming. One of those countries, where nothing can be bought and only the streaming subscription is offered, is Mexico.", QbzSession.trRev)
-                    color: theme.textSecondary
-                    font.pixelSize: 13
-                    wrapMode: Text.WordWrap
-                }
-                Text {
-                    width: parent.width
-                    text: QbzSession.tr("As it happens, the developer and maintainer of this software is from Mexico, so this section was built in blind mode — 'I am one with the Force and the Force is with me' — with some feedback from a couple of contributors, but in the end, in blind mode: it ships with no guarantee that it works and no promise to fix whatever is broken.", QbzSession.trRev)
-                    color: theme.textSecondary
-                    font.pixelSize: 13
-                    wrapMode: Text.WordWrap
-                }
-                Item {
-                    width: parent.width
-                    height: 32
-                    QbzPrimaryButton {
-                        anchors.right: parent.right
-                        label: QbzSession.tr("OK", QbzSession.trRev)
-                        btnHeight: 32
-                        onClicked: QbzPurchases.dismissDisclaimer()
-                    }
-                }
-            }
-        }
-    }
 }