feat: keyboard bottom-row layout, handedness preference, and screen wake lock

Rework the action cluster to a mic-above-bottom-row layout, add left/right
handedness setting that swaps delete and return, and keep the screen awake
during Flow recording sessions.

OSGKeyboardShared/Models/HandednessPreference.swift

@@ -0,0 +1,29 @@
+// HandednessPreference.swift
+// OSGKeyboard · Shared
+//
+// Which hand the user holds the phone with — controls bottom-row key order
+// on the keyboard (delete ↔ return swap for right-handed use).
+
+import Foundation
+
+public enum HandednessPreference: String, CaseIterable, Identifiable, Sendable, Codable {
+    case left
+    case right
+
+    public var id: String { rawValue }
+
+    public var labelKey: String {
+        switch self {
+        case .left:  return "settings.handedness.left"
+        case .right: return "settings.handedness.right"
+        }
+    }
+
+    /// Right-handed preference places return on the left and delete on the right.
+    public var swapsActionKeys: Bool { self == .right }
+
+    public static func fromStored(_ raw: String?) -> HandednessPreference {
+        guard let raw, let value = HandednessPreference(rawValue: raw) else { return .left }
+        return value
+    }
+}