Default to Sonnet 4.5 in BYOK (#39132)

<img width="381" height="204" alt="Screenshot 2025-09-29 at 2 29 58 PM"
src="https://github.com/user-attachments/assets/c7aaf0b0-b09b-4ed9-8113-8d7b18eefc2f"
/>


Release Notes:

- Claude Sonnet 4.5 and 4.5 Thinking are now the recommended Anthropic
models

crates/anthropic/src/anthropic.rs

@@ -67,7 +67,6 @@ pub enum Model {
         alias = "claude-opus-4-1-thinking-latest"
     )]
     ClaudeOpus4_1Thinking,
-    #[default]
     #[serde(rename = "claude-sonnet-4", alias = "claude-sonnet-4-latest")]
     ClaudeSonnet4,
     #[serde(
@@ -75,6 +74,7 @@ pub enum Model {
         alias = "claude-sonnet-4-thinking-latest"
     )]
     ClaudeSonnet4Thinking,
+    #[default]
     #[serde(rename = "claude-sonnet-4-5", alias = "claude-sonnet-4-5-latest")]
     ClaudeSonnet4_5,
     #[serde(

crates/bedrock/src/models.rs

@@ -22,7 +22,6 @@ pub struct BedrockModelCacheConfiguration {
 #[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq, EnumIter)]
 pub enum Model {
     // Anthropic models (already included)
-    #[default]
     #[serde(rename = "claude-sonnet-4", alias = "claude-sonnet-4-latest")]
     ClaudeSonnet4,
     #[serde(
@@ -30,6 +29,7 @@ pub enum Model {
         alias = "claude-sonnet-4-thinking-latest"
     )]
     ClaudeSonnet4Thinking,
+    #[default]
     #[serde(rename = "claude-sonnet-4-5", alias = "claude-sonnet-4-5-latest")]
     ClaudeSonnet4_5,
     #[serde(

crates/language_models/src/provider/anthropic.rs

@@ -151,8 +151,8 @@ impl LanguageModelProvider for AnthropicLanguageModelProvider {
 
     fn recommended_models(&self, _cx: &App) -> Vec<Arc<dyn LanguageModel>> {
         [
-            anthropic::Model::ClaudeSonnet4,
-            anthropic::Model::ClaudeSonnet4Thinking,
+            anthropic::Model::ClaudeSonnet4_5,
+            anthropic::Model::ClaudeSonnet4_5Thinking,
         ]
         .into_iter()
         .map(|model| self.create_language_model(model))