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/FlowUtteranceChunkConfig.swift

@@ -1,7 +1,7 @@
 // FlowUtteranceChunkConfig.swift
 // OSGKeyboard · Shared
 //
-// Chunking policy for pipelined Flow utterance ASR (up to 3 minutes).
+// Chunking policy for pipelined Flow utterance ASR (up to 3.5 minutes).
 
 import Foundation
 

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
+    }
+}

OSGKeyboardShared/Models/ProviderConfig.swift

@@ -52,6 +52,7 @@ public final class ProviderConfig: ObservableObject, @unchecked Sendable {
         // "on" state during init, but new writes never touch the key.
         static let translationTargetLocaleId = "config.translationTargetLocaleId"
         static let polishScenarioId = "config.polishScenarioId"
+        static let handednessPreference = "config.handednessPreference"
     }
 
     @Published public var providerId: String {
@@ -163,6 +164,14 @@ public final class ProviderConfig: ObservableObject, @unchecked Sendable {
             AppGroupConfigDarwin.postConfigChanged()
         }
     }
+    /// Which hand the user holds the phone with — mirrors to the keyboard
+    /// extension so delete / return can swap on the bottom row.
+    @Published public var handednessPreference: HandednessPreference {
+        didSet {
+            defaults.set(handednessPreference.rawValue, forKey: Key.handednessPreference)
+            AppGroupConfigDarwin.postConfigChanged()
+        }
+    }
 
     /// Whether the pipeline should run translate-and-polish (not just
     /// polish). Cloud engine: any selected target locale. Local engine:
@@ -299,6 +308,9 @@ public final class ProviderConfig: ObservableObject, @unchecked Sendable {
                 self.polishScenarioId = PolishScenarioCatalog.defaultId
             }
         }
+        self.handednessPreference = HandednessPreference.fromStored(
+            resolvedDefaults.string(forKey: Key.handednessPreference)
+        )
 
         // Cloud no longer exposes off/transcribe; migrate legacy values.
         if self.engineMode == "cloud", self.modeId != "polish" {
@@ -350,6 +362,7 @@ public final class ProviderConfig: ObservableObject, @unchecked Sendable {
         model = preset.defaultModel
         systemPrompt = AppGroupStore.defaultSystemPrompt(for: "openai")
         polishScenarioId = PolishScenarioCatalog.defaultId
+        handednessPreference = .left
         hasAcknowledgedCloudSharing = false
     }
 }

OSGKeyboardShared/Services/AppGroupStore.swift

@@ -46,6 +46,7 @@ public struct AppGroupStore: @unchecked Sendable {
         // computed shim for source compatibility.
         static let translationTargetLocaleId = "config.translationTargetLocaleId"
         static let polishScenarioId = "config.polishScenarioId"
+        static let handednessPreference = "config.handednessPreference"
     }
 
     // MARK: - Reads
@@ -133,6 +134,11 @@ public struct AppGroupStore: @unchecked Sendable {
         return PolishScenarioCatalog.resolve(stored ?? PolishScenarioCatalog.defaultId).id
     }
 
+    /// Bottom-row key order on the keyboard extension.
+    public var handednessPreference: HandednessPreference {
+        HandednessPreference.fromStored(defaults.string(forKey: Key.handednessPreference))
+    }
+
     // MARK: - Writes
 
     public func setModeId(_ id: String) {
@@ -184,6 +190,11 @@ public struct AppGroupStore: @unchecked Sendable {
         AppGroupConfigDarwin.postConfigChanged()
     }
 
+    public func setHandednessPreference(_ preference: HandednessPreference) {
+        defaults.set(preference.rawValue, forKey: Key.handednessPreference)
+        AppGroupConfigDarwin.postConfigChanged()
+    }
+
     /// Whether ASR output should be sent through the cloud LLM step.
     /// Cloud engine: always. Local engine: only when cloud polish is
     /// enabled (translation is a sub-option of that step).

OSGKeyboardShared/Services/FlowSessionKeys.swift

@@ -24,8 +24,8 @@ public enum FlowSessionKeys {
     /// Default Flow session length when started from the keyboard.
     public static let defaultSessionDuration: TimeInterval = 480
 
-    /// Maximum duration for a single keyboard utterance (3 minutes).
-    public static let maxUtteranceDuration: TimeInterval = 180
+    /// Maximum duration for a single keyboard utterance (3.5 minutes).
+    public static let maxUtteranceDuration: TimeInterval = 210
 
     /// Host polls for pipelined ASR drain after mic stop. Pipelining usually
     /// finishes most chunks during recording; this is a soft deadline before

OSGKeyboardShared/Services/KeyboardState.swift

@@ -103,6 +103,8 @@ public final class KeyboardState: ObservableObject {
     /// v0.2.0: mirrored from App Group — local engine runs the cloud
     /// LLM step only when this is `true`.
     @Published public var localModeCloudPolishEnabled: Bool = false
+    /// Mirrored from App Group — swaps delete / return on the bottom row.
+    @Published public var handednessPreference: HandednessPreference = .left
     /// Whether translate-and-polish is actually armed for the current
     /// engine (local requires cloud polish + a target locale).
     public var isTranslationEffective: Bool {