Address backend implementation review findings

docs/roadmap/future.md

@@ -35,9 +35,10 @@ consumers.
 
 ### Backend-specific concurrency management
 
-Extend the selected
-[LLM backend registry](backends.md) with optional per-backend concurrency limits
-and bounded, buffered admission queues. Promptkit could then route simultaneous
+Extend the
+[LLM backend registry](../consumers/pkg-promptkit.md#register-a-custom-backend)
+with optional per-backend concurrency limits and bounded, buffered admission
+queues. Promptkit could then route simultaneous
 generation requests according to backend capacity while containing accidental
 runaway submission. Downstream consumers would continue invoking synchronous
 `Run` calls, including concurrently from multiple goroutines, and each