fix(api): model claude selalu pakai Opus dari settings.json, bukan deepseek

TUI turn.rs & daemon handler.rs ambil model langsung dari
settings.model (tersimpan 'deepseek-v4-flash-free' di
~/.local/share/zesdex/settings.json) padahal provider sudah 'claude'.

- feat(domain): resolve_effective_model() — saat provider claude, model
  diambil dari app_config provider claude (default_model=claude-opus-4-8
  hasil deteksi ~/.claude/settings.json), menang atas settings.model basi.
  Provider non-claude tetap hormati settings.model user.
- fix(tui): turn.rs pakai resolve_effective_model (bukan settings.model)
- fix(daemon): handler.rs run_turn + compaction pakai resolve_effective_model
- fix(data): ~/.local/share/zesdex/settings.json model deepseek -> claude-opus-4-8
- test: 3 unit test resolve_effective_model

apps/domain/src/cms/settings.rs

@@ -23,6 +23,8 @@ use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
 
+use super::app_config::AppConfig;
+
 /// Controls how much network access the agent is permitted during a session.
 ///
 /// ## Variants
@@ -112,3 +114,86 @@ impl Default for Settings {
         }
     }
 }
+
+/// Pick the effective model name for the main agent.
+///
+/// When `settings.provider` is `"claude"` (auto-detected from
+/// `~/.claude/settings.json`), the provider's `default_model` (or the
+/// app-level `default_model`) wins over a possibly-stale persisted
+/// `settings.model`. Otherwise the user's explicit `settings.model` is used.
+///
+/// Why: the user's custom Claude endpoint (URL + API key from
+/// `~/.claude/settings.json`) implies Opus as the model; a stale
+/// `settings.json` (e.g. "deepseek-v4-flash-free") must not override it.
+pub fn resolve_effective_model(settings: &Settings, app_config: &AppConfig) -> String {
+    if settings.provider == "claude" {
+        if let Some(m) = app_config
+            .providers
+            .get("claude")
+            .and_then(|p| p.default_model.clone())
+        {
+            return m;
+        }
+        return app_config.default_model.clone();
+    }
+    settings.model.clone()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::cms::app_config::AppConfig;
+
+    fn claude_app_config() -> AppConfig {
+        let mut cfg = AppConfig::default();
+        cfg.providers.insert(
+            "claude".to_string(),
+            crate::cms::ProviderConfig {
+                api_base: "https://9router.example/v1".to_string(),
+                api_key_env: Some("ANTHROPIC_API_KEY".to_string()),
+                default_model: Some("claude-opus-4-8".to_string()),
+                default_api_key: Some("sk-test".to_string()),
+            },
+        );
+        cfg.default_provider = "claude".to_string();
+        cfg.default_model = "claude-opus-4-8".to_string();
+        cfg
+    }
+
+    #[test]
+    fn claude_provider_uses_opus_model_over_stale_settings_model() {
+        let settings = Settings {
+            provider: "claude".to_string(),
+            model: "deepseek-v4-flash-free".to_string(), // stale persisted
+            ..Settings::default()
+        };
+
+        let model = resolve_effective_model(&settings, &claude_app_config());
+        assert_eq!(model, "claude-opus-4-8");
+    }
+
+    #[test]
+    fn non_claude_provider_uses_settings_model() {
+        let settings = Settings {
+            provider: "zen".to_string(),
+            model: "my-model".to_string(),
+            ..Settings::default()
+        };
+
+        let model = resolve_effective_model(&settings, &AppConfig::default());
+        assert_eq!(model, "my-model");
+    }
+
+    #[test]
+    fn claude_falls_back_to_app_default() {
+        let settings = Settings {
+            provider: "claude".to_string(),
+            model: String::new(),
+            ..Settings::default()
+        };
+
+        let cfg = AppConfig::default();
+        let model = resolve_effective_model(&settings, &cfg);
+        assert_eq!(model, cfg.default_model);
+    }
+}