feat: first cut at dev brain

src/config.rs

@@ -15,6 +15,7 @@ pub struct Config {
     pub model: ModelChoice,
     pub idle_timeout_minutes: i32,
     pub a2ui_enabled: bool,
+    pub dev_brain: DevBrainConfig,
     pub endpoint: EndpointConfig,
     pub generation: GenerationPreferences,
     pub runtime: RuntimePreferences,
@@ -27,6 +28,7 @@ impl Default for Config {
             model: ModelChoice::default(),
             idle_timeout_minutes: 10,
             a2ui_enabled: true,
+            dev_brain: DevBrainConfig::default(),
             endpoint: EndpointConfig::default(),
             generation: GenerationPreferences::default(),
             runtime: RuntimePreferences::default(),
@@ -35,6 +37,35 @@ impl Default for Config {
     }
 }
 
+#[derive(Clone, Debug, Default, Deserialize, Eq, PartialEq, Serialize)]
+#[serde(default, deny_unknown_fields)]
+pub struct DevBrainConfig {
+    pub enabled: bool,
+    pub vault_path: Option<String>,
+}
+
+impl DevBrainConfig {
+    pub fn vault(&self) -> Result<std::path::PathBuf, String> {
+        if !self.enabled {
+            return Err("Dev Brain is disabled.".into());
+        }
+        let path = self
+            .vault_path
+            .as_deref()
+            .filter(|path| !path.trim().is_empty())
+            .ok_or_else(|| "Choose an Obsidian vault before enabling Dev Brain.".to_owned())?;
+        crate::dev_brain::validate_vault(Path::new(path))
+    }
+
+    fn validate(&self) -> Result<(), String> {
+        if self.enabled {
+            self.vault().map(|_| ())
+        } else {
+            Ok(())
+        }
+    }
+}
+
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 #[serde(default, deny_unknown_fields)]
 pub struct EndpointConfig {
@@ -113,7 +144,8 @@ impl Config {
             return Err("Endpoint port must be between 1 and 65535.".into());
         }
         self.generation.validate()?;
-        self.runtime.validate(self.model)
+        self.runtime.validate(self.model)?;
+        self.dev_brain.validate()
     }
 }