refactor: rename Server → Space across entire codebase

Renames all domain terminology from "Server" to "Space" throughout the
application — database schema, API routes, shared types, stores, components,
and UI strings. Files renamed: ServerSidebar → SpaceSidebar, CreateServer →
CreateSpace, JoinServer → JoinSpace, ServerSettings → SpaceSettings,
serverStore → spaceStore, routes/servers → routes/spaces.

packages/server/src/routes/users.ts

@@ -120,9 +120,9 @@ export async function userRoutes(app: FastifyInstance): Promise<void> {
 
     // Broadcast presence update if status changed
     if (status !== undefined) {
-      const userServers = connectionManager.getUserServers(sanitized.id);
-      for (const serverId of userServers) {
-        connectionManager.sendToServer(serverId, {
+      const userSpaces = connectionManager.getUserSpaces(sanitized.id);
+      for (const spaceId of userSpaces) {
+        connectionManager.sendToSpace(spaceId, {
           type: 'presence_update',
           userId: sanitized.id,
           status: status,