Add Claude Fable 5 pricing ($10/$50 per 1M tokens)

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

oAI/Providers/AnthropicProvider.swift

@@ -77,6 +77,15 @@ class AnthropicProvider: AIProvider {
     /// falls back to prefix matching so newly-released model variants (e.g. "claude-sonnet-4-6-20260301")
     /// still inherit the correct pricing tier.
     private static let knownModels: [ModelInfo] = [
+        // Claude Fable 5
+        ModelInfo(
+            id: "claude-fable-5",
+            name: "Claude Fable 5",
+            description: "Anthropic's creative and storytelling model",
+            contextLength: 200_000,
+            pricing: .init(prompt: 10.0, completion: 50.0),
+            capabilities: .init(vision: true, tools: true, online: true)
+        ),
         // Claude 4.x series
         ModelInfo(
             id: "claude-opus-4-6",
@@ -173,6 +182,7 @@ class AnthropicProvider: AIProvider {
     /// Pricing tiers used for fuzzy fallback matching on unknown model IDs.
     /// Keyed by model name prefix (longest match wins).
     private static let pricingFallback: [(prefix: String, prompt: Double, completion: Double)] = [
+        ("claude-fable",  10.0, 50.0),
         ("claude-opus",   15.0, 75.0),
         ("claude-sonnet",  3.0, 15.0),
         ("claude-haiku",   0.80, 4.0),