Add Anthropic Claude models via OpenRouter

Add Claude Opus 4.8, Claude Sonnet and Claude Haiku as selectable
chat models, routed through OpenRouter (provider: openrouter). Slugs
and pricing taken from the OpenRouter model list. Requires
openrouter_api_key to be set.

config/models.yml

@@ -1,4 +1,4 @@
-available_text_models: ["gpt-4o-mini", "openai/gpt-5.5", "gpt-4o", "gpt-3.5-turbo", "gpt-3.5-turbo-16k", "gpt-4-1106-preview", "gpt-4-vision-preview", "gpt-4"]
+available_text_models: ["gpt-4o-mini", "openai/gpt-5.5", "gpt-4o", "anthropic/claude-opus-4.8", "anthropic/claude-sonnet-latest", "anthropic/claude-haiku-latest", "gpt-3.5-turbo", "gpt-3.5-turbo-16k", "gpt-4-1106-preview", "gpt-4-vision-preview", "gpt-4"]
 
 info:
   gpt-3.5-turbo:
@@ -105,6 +105,48 @@ info:
       Fast: 3
       Cheap: 2
 
+  anthropic/claude-opus-4.8:
+    type: chat_completion
+    provider: openrouter
+    name: Claude Opus 4.8
+    description: Anthropic's most capable model — top-tier reasoning, coding and long-context work. Routed via <b>OpenRouter</b> (requires openrouter_api_key).
+
+    price_per_1000_input_tokens: 0.005
+    price_per_1000_output_tokens: 0.025
+
+    scores:
+      Smart: 5
+      Fast: 2
+      Cheap: 2
+
+  anthropic/claude-sonnet-latest:
+    type: chat_completion
+    provider: openrouter
+    name: Claude Sonnet
+    description: Anthropic's balanced model — strong quality with good speed and price. Routed via <b>OpenRouter</b> (requires openrouter_api_key).
+
+    price_per_1000_input_tokens: 0.003
+    price_per_1000_output_tokens: 0.015
+
+    scores:
+      Smart: 5
+      Fast: 4
+      Cheap: 3
+
+  anthropic/claude-haiku-latest:
+    type: chat_completion
+    provider: openrouter
+    name: Claude Haiku
+    description: Anthropic's fastest and most affordable model for everyday tasks. Routed via <b>OpenRouter</b> (requires openrouter_api_key).
+
+    price_per_1000_input_tokens: 0.001
+    price_per_1000_output_tokens: 0.005
+
+    scores:
+      Smart: 4
+      Fast: 5
+      Cheap: 4
+
   dalle-2:
      type: image
      price_per_1_image: 0.018  # 512x512