docs(planning): repoint two stray bare engineering.md refs

deferred.md had a now-broken markdown link to engineering.md §8 (roadmap,
dissolved); 0.6.0 release note had a bare engineering.md §2 prose ref. Both
missed in the link-repoint pass because they lacked the planning/ prefix.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

planning/deferred.md

@@ -2,7 +2,7 @@
 
 Items raised in reviews that are real but not actionable now.
 
-As of 0.7.0, all planned epics (3, 4, 5, 6) are closed — see [`engineering.md`](engineering.md) §8. The Open section below is the long-tail register: items that remain technically real but depend on speculative future work, so they're parked here pending a concrete trigger.
+As of 0.7.0, all planned epics (3, 4, 5, 6) are closed — see the [change Index](README.md). The Open section below is the long-tail register: items that remain technically real but depend on speculative future work, so they're parked here pending a concrete trigger.
 
 ## Open
 

planning/releases/0.6.0.md

@@ -18,7 +18,7 @@ This release adds operational-event emission to `Retry` and `Bulkhead` via two c
 Purely additive:
 - All previously-shipping methods behave identically.
 - Successful retries and successful bulkhead acquisitions emit nothing — the four events fire only on operational concern.
-- Per `engineering.md §2`, httpware never configures handlers, levels, or calls `logging.basicConfig()`. Consumers own their logging configuration.
+- Per `architecture/overview.md`, httpware never configures handlers, levels, or calls `logging.basicConfig()`. Consumers own their logging configuration.
 - The `otel` extra is opt-in — `pip install httpware` continues to work without `opentelemetry-api`.
 
 ## Usage