docs: stop implying matrix/bash/forge is a closed todo-producer list

docs/web-ui/agent.md

@@ -162,8 +162,10 @@ are acked, the harness won't receive wake-prompts for them. A `{
 marked: N }` pill surfaces the count. After the drain the inbox list
 empties on reload (the filter is `acked_at IS NULL`, so drained
 messages disappear). Todos flyout ("loose-ends v2"): the harness-local
-todos other subsystems (matrix, forge, bash) push at this agent
-(`GET /api/todos`) — each row shows the producing subsystem, an
+todos other subsystems push at this agent (`GET /api/todos`) — matrix,
+forge, and bash are the built-in producers, but any user-configured MCP
+server can push its own via the same in-agent socket. Each row shows the
+producing subsystem, an
 optional source label, a summary, and age. A checkbox per row plus a
 select-all / select-none / `✓ mark done` bulk row above the list POSTs
 the checked ids to `POST /api/todos/mark-done`, which dismisses them