Add Anthropic API integration, remove locale settings UI

Anthropic API:
- Add @anthropic-ai/sdk with adapter wrapping OpenAI-shaped interface
- Support Claude models (opus, sonnet, haiku) with extended thinking
- Auto-reset model on provider switch, JSON retry logic
- Add Claude model pricing to ai-usage tracker
- Update AI settings form with Anthropic provider option
- Add provider field to AIUsageLog for cross-provider cost tracking

Locale Settings Removal:
- Strip Localization tab from admin settings (mobile + desktop)
- Remove i18n settings from router and feature flags
- Remove LOCALIZATION from SettingCategory enum
- Keep franc document language detection intact

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prisma/schema.prisma

@@ -101,7 +101,6 @@ enum SettingCategory {
   DEFAULTS
   WHATSAPP
   AUDIT_CONFIG
-  LOCALIZATION
   DIGEST
   ANALYTICS
   INTEGRATIONS
@@ -907,7 +906,8 @@ model AIUsageLog {
   entityId   String?
 
   // What was used
-  model            String // gpt-4o, gpt-4o-mini, o1, etc.
+  model            String // gpt-4o, gpt-4o-mini, o1, claude-sonnet-4-5, etc.
+  provider         String? // openai, anthropic, litellm
   promptTokens     Int
   completionTokens Int
   totalTokens      Int