chore(release): bump version to 2.1.6 (build 131)

Version: CURRENT_PROJECT_VERSION 130 -> 131 (project.yml, AGENTS.md, READMEs,
docs/llms.txt).

fix(flow): host-app identification now compiles in every build configuration
(Debug, TestFlight, Release). The arbiter probe and HostAppIdentity were
DEBUG-only, so TestFlight/App Store builds never knew the host bundle id and
could not auto-return after a startflow handoff. Debug-only logging and the
Home test card are unchanged.

Also includes the pending work in the tree:
- Home: single account/setup card surface (HomeAccountSurfacePolicy/Views)
- Wide screens: voice key row and centred mic placement, iPhone Duo layout
- Keyboard: clipboard skill ranking and AI skill layout updates
- Debug: account session handoff to the Simulator (+ import script)
- Docs: portfolio assets, privacy policy URL, site/README refresh

OSGKeyboardShared/Services/AppGroupStore.swift

@@ -498,6 +498,12 @@ public struct AppGroupStore: @unchecked Sendable {
             if storedMigrationVersion < 8 {
                 additionIDs.insert(AIClipboardSkillCatalog.blessingReplyID)
             }
+            if storedMigrationVersion < 12 {
+                // Translate-to-target and Polish ship as defaults; install them
+                // once for existing layouts (a later opt-out stays opted out).
+                additionIDs.insert(AIClipboardSkillCatalog.translateToTargetID)
+                additionIDs.insert(AIClipboardSkillCatalog.polishOriginalID)
+            }
             // v9 consolidates playful and business reply into Reply. Do not
             // add Reply here: `sanitized` preserves it only when any reply ID
             // was enabled, so a user's explicit disabled state stays disabled.
@@ -529,7 +535,7 @@ public struct AppGroupStore: @unchecked Sendable {
         }
     }
 
-    private static let currentAgentSkillDefaultsMigrationVersion = 11
+    private static let currentAgentSkillDefaultsMigrationVersion = 12
 
     private static func decodeUserSkillCatalog(from defaults: UserDefaults) -> AIUserSkillCatalog {
         guard let data = defaults.data(forKey: AppGroupConfiguration.Keys.agentUserSkillCatalog) else {