Restore codebase deleted by bad auto-commit e4227cf

Commit e4227cf (a story creation auto-commit) erroneously deleted 175
files from master's tree, likely due to a race condition between
concurrent git operations. This commit re-adds all files from the
working directory.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/http/chat.rs

@@ -0,0 +1,58 @@
+use crate::http::context::{AppContext, OpenApiResult, bad_request};
+use crate::llm::chat;
+use poem_openapi::{OpenApi, Tags, payload::Json};
+use std::sync::Arc;
+
+#[derive(Tags)]
+enum ChatTags {
+    Chat,
+}
+
+pub struct ChatApi {
+    pub ctx: Arc<AppContext>,
+}
+
+#[OpenApi(tag = "ChatTags::Chat")]
+impl ChatApi {
+    /// Cancel the currently running chat stream, if any.
+    ///
+    /// Returns `true` once the cancellation signal is issued.
+    #[oai(path = "/chat/cancel", method = "post")]
+    async fn cancel_chat(&self) -> OpenApiResult<Json<bool>> {
+        chat::cancel_chat(&self.ctx.state).map_err(bad_request)?;
+        Ok(Json(true))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tempfile::TempDir;
+
+    fn test_api(dir: &TempDir) -> ChatApi {
+        ChatApi {
+            ctx: Arc::new(AppContext::new_test(dir.path().to_path_buf())),
+        }
+    }
+
+    #[tokio::test]
+    async fn cancel_chat_returns_true() {
+        let dir = TempDir::new().unwrap();
+        let api = test_api(&dir);
+        let result = api.cancel_chat().await;
+        assert!(result.is_ok());
+        assert!(result.unwrap().0);
+    }
+
+    #[tokio::test]
+    async fn cancel_chat_sends_cancel_signal() {
+        let dir = TempDir::new().unwrap();
+        let api = test_api(&dir);
+        let mut cancel_rx = api.ctx.state.cancel_rx.clone();
+        cancel_rx.borrow_and_update();
+
+        api.cancel_chat().await.unwrap();
+
+        assert!(*cancel_rx.borrow());
+    }
+}