feat: first time automated ollama install experience and openrouter (#3881)

Co-authored-by: Zane Staggs <zane@squareup.com>

crates/goose/src/providers/openrouter.rs

@@ -202,6 +202,12 @@ fn create_request_based_on_model(
         payload = update_request_for_anthropic(&payload);
     }
 
+    // Always add transforms: ["middle-out"] for OpenRouter to handle prompts > context size
+    payload
+        .as_object_mut()
+        .unwrap()
+        .insert("transforms".to_string(), json!(["middle-out"]));
+
     Ok(payload)
 }