Select inventory namespaces before copying

docs/roadmap/implementation.md

@@ -543,6 +543,20 @@ IDs, All/default/views, missing matches, mutation, and cancellation. Repeat the
 baseline through the new select-before-copy path. No persistent buckets/cache,
 new public signature, or unqualified-query complexity promise is required.
 
+Completion: namespace selection now precedes copying for all three inventories;
+focused listing and ownership tests pass on Go 1.27.3. The documented 100-iteration,
+three-run engine workload measured the following bytes/op, in All / sparse /
+dense / absent order (one allocation except absent, which used none):
+
+| Total IDs | Bytes/op |
+| --- | --- |
+| 32 | 512 / 16 / 256 / 0 |
+| 1,024 | 18,432 / 16 / 9,472 / 0 |
+| 4,096 | 65,536 / 16 / 32,768 / 0 |
+
+The baseline included full-inventory copying and subsequent filtering; these
+measurements are observations, not performance guarantees.
+
 ## Stage 21: Put Authentication Protocol Mechanics In The Outbound Adapter
 
 **Catalog:** 26. **Files:** llm authentication adapter, selection, assembly and tests.