feat(ai): unify reply center and refresh keyboard AI features

- Merge invitation, task, blessing, clarification, and empathy actions
  into a single Reply flow, with three fixed, clearly labeled stance
  choices whenever user intent must not be guessed.
- Refine clipboard semantic routing with bilingual schedule,
  confirmation, and follow-up models, conservative language thresholds,
  and explicit-assignment guard for complaint-only text.
- Persist Apple account refresh state, harden session recovery, and
  surface durable account diagnostics across keyboard and app.
- Derive personal-style prompts through two-stage corpus evidence and
  apply real low-confidence ASR tendencies instead of neutral templates.
- Localize the new reply center, clipboard semantics, and personal-style
  surfaces in both English and Simplified Chinese.

OSGKeyboardShared/Models/AISessionState.swift

@@ -122,7 +122,7 @@ public struct AISessionState: Equatable, Sendable {
         phase == .ready
             && answer == nil
             && selectedReplyVariant == nil
-            && replyVariants.count == AIReplyVariant.Kind.allCases.count
+            && AIReplyVariantSet.resolve(kinds: Set(replyVariants.map(\.kind))) != nil
     }
 
     public var canSend: Bool {
@@ -201,12 +201,12 @@ public struct AISessionState: Equatable, Sendable {
     ) {
         guard isActive, activeUtteranceID == utteranceID else { return }
         let kinds = Set(variants.map(\.kind))
-        guard variants.count == AIReplyVariant.Kind.allCases.count,
-              kinds == Set(AIReplyVariant.Kind.allCases) else {
+        guard let variantSet = AIReplyVariantSet.resolve(kinds: kinds),
+              variants.count == variantSet.kinds.count else {
             return
         }
         answer = nil
-        replyVariants = AIReplyVariant.Kind.allCases.compactMap { kind in
+        replyVariants = variantSet.kinds.compactMap { kind in
             variants.first { $0.kind == kind }
         }
         selectedReplyVariant = nil