Fix LLM routing bug and container permission errors

The default model `anthropic/claude-sonnet-4.6` was being routed to
OpenRouter (due to the `/` in the name) instead of the Anthropic API,
causing all review requests to fail with "Failed to send request to
OpenAI". Fix by:

1. Changing default model to `claude-sonnet-4-6` (no vendor prefix)
2. Adding `anthropic/` vendor prefix routing to AnthropicAdapter
   (other vendor prefixes still route to OpenRouter)

Also fix container permission denied errors by adding a non-root user
(UID 1000) to the Dockerfile with pre-created data directories,
matching the k8s securityContext that enforces runAsUser: 1000.

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

Author: haasonsaas

Dockerfile

@@ -33,8 +33,17 @@ FROM alpine:3.19
 
 RUN apk add --no-cache ca-certificates git
 
+RUN addgroup -g 1000 diffscope && \
+    adduser -u 1000 -G diffscope -h /home/diffscope -s /bin/sh -D diffscope && \
+    mkdir -p /home/diffscope/.local/share/diffscope \
+             /home/diffscope/.diffscope && \
+    chown -R diffscope:diffscope /home/diffscope
+
 COPY --from=builder /app/target/release/diffscope /usr/local/bin/diffscope
 
+USER diffscope
+WORKDIR /home/diffscope
+
 EXPOSE 3000
 
 ENTRYPOINT ["diffscope"]

charts/diffscope/values.yaml

@@ -18,7 +18,7 @@ serviceAccount:
 diffscope:
   host: "0.0.0.0"
   port: 3000
-  model: "anthropic/claude-sonnet-4.6"
+  model: "claude-sonnet-4-6"
   # Adapter override: openai, anthropic, ollama, openrouter (auto-detected if empty)
   adapter: ""
   # Base URL for LLM API (auto-set to Ollama service URL when ollama.enabled)

src/adapters/llm.rs

@@ -26,7 +26,7 @@ pub struct ModelConfig {
 impl Default for ModelConfig {
     fn default() -> Self {
         Self {
-            model_name: "anthropic/claude-sonnet-4.6".to_string(),
+            model_name: "claude-sonnet-4-6".to_string(),
             api_key: None,
             base_url: None,
             temperature: 0.2,
@@ -98,13 +98,26 @@ pub fn create_adapter(config: &ModelConfig) -> Result<Box<dyn LLMAdapter>> {
         };
     }
 
-    // OpenRouter-style model IDs (vendor/model)
+    // Vendor-prefixed model IDs (vendor/model)
     if config.model_name.contains('/') {
-        let mut or_config = config;
-        if or_config.base_url.is_none() {
-            or_config.base_url = Some("https://openrouter.ai/api/v1".to_string());
+        let (vendor, model) = config.model_name.split_once('/').unwrap();
+        let model = model.to_string();
+        match vendor {
+            "anthropic" => {
+                // Route anthropic/ prefix directly to the Anthropic adapter
+                let mut anth_config = config;
+                anth_config.model_name = model;
+                return Ok(Box::new(crate::adapters::AnthropicAdapter::new(anth_config)?));
+            }
+            _ => {
+                // Other vendor prefixes (e.g. openai/, meta-llama/) → OpenRouter
+                let mut or_config = config;
+                if or_config.base_url.is_none() {
+                    or_config.base_url = Some("https://openrouter.ai/api/v1".to_string());
+                }
+                return Ok(Box::new(crate::adapters::OpenAIAdapter::new(or_config)?));
+            }
         }
-        return Ok(Box::new(crate::adapters::OpenAIAdapter::new(or_config)?));
     }
 
     // Model-name heuristic
@@ -306,10 +319,19 @@ mod tests {
         let _adapter = create_adapter(&config).unwrap();
     }
 
+    #[test]
+    fn test_create_adapter_anthropic_vendor_prefix() {
+        // anthropic/ prefix should route to AnthropicAdapter, not OpenRouter
+        let config = local_config("anthropic/claude-sonnet-4-6");
+        let adapter = create_adapter(&config).unwrap();
+        // The adapter strips the vendor prefix
+        assert_eq!(adapter.model_name(), "claude-sonnet-4-6");
+    }
+
     #[test]
     fn test_model_config_default() {
         let config = ModelConfig::default();
-        assert_eq!(config.model_name, "anthropic/claude-sonnet-4.6");
+        assert_eq!(config.model_name, "claude-sonnet-4-6");
         assert!(config.api_key.is_none());
         assert!(config.base_url.is_none());
         assert!((config.temperature - 0.2).abs() < f32::EPSILON);

src/config.rs

@@ -968,7 +968,7 @@ impl Config {
 }
 
 fn default_model() -> String {
-    "anthropic/claude-sonnet-4.6".to_string()
+    "claude-sonnet-4-6".to_string()
 }
 
 fn default_temperature() -> f32 {

src/main.rs

@@ -26,7 +26,7 @@ struct Cli {
     #[command(subcommand)]
     command: Commands,
 
-    #[arg(long, global = true, default_value = "anthropic/claude-sonnet-4.6")]
+    #[arg(long, global = true, default_value = "claude-sonnet-4-6")]
     model: String,
 
     #[arg(

web/src/pages/Settings.tsx

@@ -473,7 +473,7 @@ export function Settings() {
         </div>
 
         <div className="space-y-3 border-t border-border-subtle pt-3">
-          {field('Model name', 'model', 'text', 'anthropic/claude-sonnet-4.6', 'OpenRouter: vendor/model-name')}
+          {field('Model name', 'model', 'text', 'claude-sonnet-4-6', 'Direct: claude-*, gpt-* | OpenRouter: vendor/model')}
           {selectField('Adapter', 'adapter', [
             { value: '', label: 'Auto-detect' },
             { value: 'openai', label: 'OpenAI (direct)' },