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/Services/LLMClient.swift

@@ -12,6 +12,7 @@ public enum LLMError: Error, LocalizedError, Sendable, Equatable {
     case http(status: Int)
     case decoding(String)
     case transport(String)
+    case timeout
     case cancelled
     case rateLimited
 
@@ -27,6 +28,8 @@ public enum LLMError: Error, LocalizedError, Sendable, Equatable {
             return SharedL10n.string("error.llm.decoding")
         case .transport:
             return SharedL10n.string("error.llm.transport")
+        case .timeout:
+            return SharedL10n.string("error.llm.timeout")
         case .rateLimited:
             return SharedL10n.string("error.llm.rateLimited")
         case .cancelled:
@@ -291,6 +294,8 @@ public struct OpenAICompatibleClient: LLMClient {
             throw LLMError.cancelled
         } catch let urlError as URLError where urlError.code == .cancelled {
             throw LLMError.cancelled
+        } catch let urlError as URLError where urlError.code == .timedOut {
+            throw LLMError.timeout
         } catch {
             throw LLMError.transport(String(describing: error))
         }