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>

src/server/utils/ai-usage.ts

@@ -29,6 +29,7 @@ export interface LogAIUsageInput {
   entityType?: string
   entityId?: string
   model: string
+  provider?: string
   promptTokens: number
   completionTokens: number
   totalTokens: number
@@ -98,6 +99,13 @@ const MODEL_PRICING: Record<string, ModelPricing> = {
 
   // o4 reasoning models (future-proofing)
   'o4-mini': { input: 1.1, output: 4.4 },
+
+  // Anthropic Claude models
+  'claude-opus-4-5-20250514': { input: 15.0, output: 75.0 },
+  'claude-sonnet-4-5-20250514': { input: 3.0, output: 15.0 },
+  'claude-haiku-3-5-20241022': { input: 0.8, output: 4.0 },
+  'claude-opus-4-20250514': { input: 15.0, output: 75.0 },
+  'claude-sonnet-4-20250514': { input: 3.0, output: 15.0 },
 }
 
 // Default pricing for unknown models (conservative estimate)
@@ -150,6 +158,16 @@ function getModelPricing(model: string): ModelPricing {
   if (modelLower.startsWith('o4')) {
     return MODEL_PRICING['o4-mini'] || DEFAULT_PRICING
   }
+  // Anthropic Claude prefix fallbacks
+  if (modelLower.startsWith('claude-opus')) {
+    return { input: 15.0, output: 75.0 }
+  }
+  if (modelLower.startsWith('claude-sonnet')) {
+    return { input: 3.0, output: 15.0 }
+  }
+  if (modelLower.startsWith('claude-haiku')) {
+    return { input: 0.8, output: 4.0 }
+  }
 
   return DEFAULT_PRICING
 }
@@ -200,6 +218,7 @@ export async function logAIUsage(input: LogAIUsageInput): Promise<void> {
         entityType: input.entityType,
         entityId: input.entityId,
         model: input.model,
+        provider: input.provider,
         promptTokens: input.promptTokens,
         completionTokens: input.completionTokens,
         totalTokens: input.totalTokens,