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/matrix/transport_impl.rs

@@ -0,0 +1,96 @@
+//! Matrix implementation of [`ChatTransport`].
+//!
+//! Wraps a [`matrix_sdk::Client`] and delegates message sending / editing
+//! to the Matrix SDK.
+
+use async_trait::async_trait;
+use matrix_sdk::Client;
+use matrix_sdk::ruma::OwnedRoomId;
+use matrix_sdk::ruma::events::room::message::{
+    ReplacementMetadata, RoomMessageEventContent, RoomMessageEventContentWithoutRelation,
+};
+
+use crate::transport::{ChatTransport, MessageId};
+
+/// Matrix-backed [`ChatTransport`] implementation.
+///
+/// Holds a [`Client`] and resolves room IDs at send time.
+pub struct MatrixTransport {
+    client: Client,
+}
+
+impl MatrixTransport {
+    pub fn new(client: Client) -> Self {
+        Self { client }
+    }
+}
+
+#[async_trait]
+impl ChatTransport for MatrixTransport {
+    async fn send_message(
+        &self,
+        room_id: &str,
+        plain: &str,
+        html: &str,
+    ) -> Result<MessageId, String> {
+        let room_id: OwnedRoomId = room_id
+            .parse()
+            .map_err(|e| format!("Invalid room ID '{room_id}': {e}"))?;
+        let room = self
+            .client
+            .get_room(&room_id)
+            .ok_or_else(|| format!("Room {room_id} not found in client state"))?;
+
+        let content = RoomMessageEventContent::text_html(plain.to_string(), html.to_string());
+        let resp = room
+            .send(content)
+            .await
+            .map_err(|e| format!("Matrix send error: {e}"))?;
+
+        Ok(resp.event_id.to_string())
+    }
+
+    async fn edit_message(
+        &self,
+        room_id: &str,
+        original_message_id: &str,
+        plain: &str,
+        html: &str,
+    ) -> Result<(), String> {
+        let room_id: OwnedRoomId = room_id
+            .parse()
+            .map_err(|e| format!("Invalid room ID '{room_id}': {e}"))?;
+        let room = self
+            .client
+            .get_room(&room_id)
+            .ok_or_else(|| format!("Room {room_id} not found in client state"))?;
+
+        let original_event_id = original_message_id
+            .parse()
+            .map_err(|e| format!("Invalid event ID '{original_message_id}': {e}"))?;
+
+        let new_content =
+            RoomMessageEventContentWithoutRelation::text_html(plain.to_string(), html.to_string());
+        let metadata = ReplacementMetadata::new(original_event_id, None);
+        let content = new_content.make_replacement(metadata);
+
+        room.send(content)
+            .await
+            .map(|_| ())
+            .map_err(|e| format!("Matrix edit error: {e}"))
+    }
+
+    async fn send_typing(&self, room_id: &str, typing: bool) -> Result<(), String> {
+        let room_id: OwnedRoomId = room_id
+            .parse()
+            .map_err(|e| format!("Invalid room ID '{room_id}': {e}"))?;
+        let room = self
+            .client
+            .get_room(&room_id)
+            .ok_or_else(|| format!("Room {room_id} not found in client state"))?;
+
+        room.typing_notice(typing)
+            .await
+            .map_err(|e| format!("Matrix typing indicator error: {e}"))
+    }
+}