feat(story-193): clickable code references in frontend

server/src/http/settings.rs

@@ -1,6 +1,6 @@
 use crate::http::context::{AppContext, OpenApiResult, bad_request};
 use crate::store::StoreOps;
-use poem_openapi::{Object, OpenApi, Tags, payload::Json};
+use poem_openapi::{Object, OpenApi, Tags, param::Query, payload::Json};
 use serde::Serialize;
 use serde_json::json;
 use std::sync::Arc;
@@ -22,6 +22,11 @@ struct EditorCommandResponse {
     editor_command: Option<String>,
 }
 
+#[derive(Debug, Object, Serialize)]
+struct OpenFileResponse {
+    success: bool,
+}
+
 pub struct SettingsApi {
     pub ctx: Arc<AppContext>,
 }
@@ -39,6 +44,32 @@ impl SettingsApi {
         Ok(Json(EditorCommandResponse { editor_command }))
     }
 
+    /// Open a file in the configured editor at the given line number.
+    ///
+    /// Invokes the stored editor CLI (e.g. "zed", "code") with `path:line` as the argument.
+    /// Returns an error if no editor is configured or if the process fails to spawn.
+    #[oai(path = "/settings/open-file", method = "post")]
+    async fn open_file(
+        &self,
+        path: Query<String>,
+        line: Query<Option<u32>>,
+    ) -> OpenApiResult<Json<OpenFileResponse>> {
+        let editor_command = get_editor_command_from_store(&self.ctx)
+            .ok_or_else(|| bad_request("No editor configured".to_string()))?;
+
+        let file_ref = match line.0 {
+            Some(l) => format!("{}:{}", path.0, l),
+            None => path.0.clone(),
+        };
+
+        std::process::Command::new(&editor_command)
+            .arg(&file_ref)
+            .spawn()
+            .map_err(|e| bad_request(format!("Failed to open editor: {e}")))?;
+
+        Ok(Json(OpenFileResponse { success: true }))
+    }
+
     /// Set the preferred editor command (e.g. "zed", "code", "cursor").
     /// Pass null or empty string to clear the preference.
     #[oai(path = "/settings/editor", method = "put")]
@@ -275,4 +306,64 @@ mod tests {
             .0;
         assert!(result.editor_command.is_none());
     }
+
+    #[tokio::test]
+    async fn open_file_returns_error_when_no_editor_configured() {
+        let dir = TempDir::new().unwrap();
+        let api = make_api(&dir);
+        let result = api
+            .open_file(Query("src/main.rs".to_string()), Query(Some(42)))
+            .await;
+        assert!(result.is_err());
+        let err = result.unwrap_err();
+        assert_eq!(err.status(), poem::http::StatusCode::BAD_REQUEST);
+    }
+
+    #[tokio::test]
+    async fn open_file_spawns_editor_with_path_and_line() {
+        let dir = TempDir::new().unwrap();
+        let api = make_api(&dir);
+        // Configure the editor to "echo" which is a safe no-op command
+        api.set_editor(Json(EditorCommandPayload {
+            editor_command: Some("echo".to_string()),
+        }))
+        .await
+        .unwrap();
+        let result = api
+            .open_file(Query("src/main.rs".to_string()), Query(Some(42)))
+            .await
+            .unwrap();
+        assert!(result.0.success);
+    }
+
+    #[tokio::test]
+    async fn open_file_spawns_editor_with_path_only_when_no_line() {
+        let dir = TempDir::new().unwrap();
+        let api = make_api(&dir);
+        api.set_editor(Json(EditorCommandPayload {
+            editor_command: Some("echo".to_string()),
+        }))
+        .await
+        .unwrap();
+        let result = api
+            .open_file(Query("src/lib.rs".to_string()), Query(None))
+            .await
+            .unwrap();
+        assert!(result.0.success);
+    }
+
+    #[tokio::test]
+    async fn open_file_returns_error_for_nonexistent_editor() {
+        let dir = TempDir::new().unwrap();
+        let api = make_api(&dir);
+        api.set_editor(Json(EditorCommandPayload {
+            editor_command: Some("this_editor_does_not_exist_xyz_abc".to_string()),
+        }))
+        .await
+        .unwrap();
+        let result = api
+            .open_file(Query("src/main.rs".to_string()), Query(Some(1)))
+            .await;
+        assert!(result.is_err());
+    }
 }