feat(keyboard): add clipboard history and undo pastes

Ship optional keyboard clipboard history with settings, suggestion strip, and paste-permission guidance; let undo roll back clipboard inserts; bump build to 64.

OSGKeyboardShared/Models/ClipboardHistoryEntry.swift

@@ -0,0 +1,26 @@
+// ClipboardHistoryEntry.swift
+// OSGKeyboard · Shared
+//
+// One persisted clipboard history row (plain text / Unicode emoji only).
+
+import Foundation
+
+public struct ClipboardHistoryEntry: Codable, Equatable, Identifiable, Sendable {
+    public let id: UUID
+    public var text: String
+    public var createdAt: Date
+    /// Pasteboard changeCount when this row was captured (best-effort).
+    public var changeCount: Int?
+
+    public init(
+        id: UUID = UUID(),
+        text: String,
+        createdAt: Date = Date(),
+        changeCount: Int? = nil
+    ) {
+        self.id = id
+        self.text = text
+        self.createdAt = createdAt
+        self.changeCount = changeCount
+    }
+}