Reuse the declaration validation path across siblings

docs/roadmap/remediation.md

@@ -1,6 +1,6 @@
 # Implementation efficiency remediation
 
-Status: one open P3 efficiency finding. Reviewed source:
+Status: R1 complete; no open findings. Audited source before remediation:
 `1cba65fffe966cb70f48c324baf551502544cbad`.
 
 ## Scope and architecture
@@ -42,7 +42,7 @@ path, rather than proposing a different algorithm or public contract.
 | 14 | Shared token consumption advances through short spellings and consumed values; it does not rescan each complete short cluster. |
 | 15 | Implementation retains the selected context-local memoization and source ordering. No residual independent suffix walks were found. |
 | 16 | Implementation uses the selected resolver tree and owned-path results for distinct-prefix discovery and descendant lookup. Those selected algorithms were not reopened. |
-| 17 | **R1:** a child's grown path slice is not retained for siblings, allowing repeated deep-prefix copying. |
+| 17 | **R1 complete:** the traversal now retains grown scratch-path capacity across siblings. |
 | 18 | Operation-preparation extraction preserves the selected independent inputs and existing preflight rules; no new repeated algorithm was introduced. |
 | 19 | Capture extraction preserves existing selector/scope processing. The explicitly deferred indexing work remains outside this audit. |
 | 20 | Operand/error attribution extraction preserves the selected dense reconstruction and replay merge, without introducing general sorting. |
@@ -52,7 +52,18 @@ path, rather than proposing a different algorithm or public contract.
 
 ## R1 — P3: Declaration validation can still copy a shared deep prefix for every sibling
 
-**Code:** [command.go](../../command.go), collectDeclarationIssues lines
+**Complete.** validateCommandPlacement now owns one path slice captured by its
+recursive collectDeclarationIssues visitor. Each node appends its name and
+defers truncation to its entry length, including on invalid/absent early returns.
+Truncation preserves the grown slice header and capacity for subsequent siblings.
+Successful traversal therefore takes O(N) amortized path work with O(D) scratch
+storage; diagnostic labels are still formatted only when emitted. Child/issue
+order, error wrapping, root-only checks and declaration handling are preserved.
+See [remediation verification](#remediation-verification) for the checks performed.
+
+The analysis below records the defect at the audited revision.
+
+**Audited code:** [command.go](../../command.go), collectDeclarationIssues lines
 450–479, particularly append at line 456 and recursive calls at line 478.
 validateCommandPlacement starts the walk with nil parents; installation reaches
 it through the candidate validator.
@@ -110,19 +121,16 @@ strings. This needs neither a public API change nor restrictions on declaration
 size or depth. It completes the selected design without promising that all App
 construction becomes linear.
 
-**Verification and status:** a temporary public consumer installed a valid
+**Audit verification:** a temporary public consumer installed a valid
 32-node shared prefix with 64 leaf siblings and dispatched a leaf successfully.
 The prefix depth was selected at an ordinary slice-capacity boundary. This
 confirms that the workload shape is accepted; it is not a timing or allocation
 measurement. The copying bound follows from the recursive slice-header ownership
 and append semantics above.
 
-Use existing declaration/registry behavioral checks to preserve results, and
-review that grown capacity survives sibling traversal. Include a branching
-shape when checking the remedy; a chain alone misses this case. No timing
-threshold or benchmark is necessary. Stage 17 and F22 are currently marked
-complete; their completion evidence should be corrected to account for this
-remaining case when remediation is performed.
+At audit time, Stage 17 and F22 were marked complete without accounting for this
+branching case. Their completion evidence now records the shared slice remedy
+and links to this follow-up.
 
 ## Validation and limits
 
@@ -133,7 +141,29 @@ cached Go 1.27.0 binary with `GOTOOLCHAIN=local`, `GOPROXY=off`, and
 Cached successful results were reused for unchanged code. Those suites validate
 behavior, not asymptotic copy costs.
 
-No production code, repository tests, manifests or existing roadmap records were
-modified. No benchmarks, performance profiles, real-world latency/memory data,
-external services, credentials or publication operations were used. No additional
-ordinary correctness defect was established during this algorithmic review.
+During the audit, no production code, repository tests, manifests or existing
+roadmap records were modified. No benchmarks, performance profiles, real-world
+latency/memory data, external services, credentials or publication operations were
+used. No additional ordinary correctness defect was established during this
+algorithmic review.
+
+## Remediation verification
+
+The focused declaration/registry checks passed uncached, including retained
+causes, absence, invalid declarations, nested root-only groups and transactional
+installation. The independent core suite and aligned three-module suite also
+passed offline using cached Go 1.27.0 with `GOTOOLCHAIN=local`, `GOPROXY=off` and
+`-mod=readonly`. The aligned command was
+`go test -mod=readonly ./... ./integrations/ckconfig/... ./integrations/ckprompt/...`;
+the independent core check used `GOWORK=off go test -mod=readonly ./...`.
+
+The temporary public consumer was rerun successfully with a valid depth-32 prefix
+and 64 leaf siblings. This checks installation and dispatch for the branching
+shape. Source inspection establishes the complexity improvement: all recursive
+calls update the same slice header, growth survives return, and each node's
+deferred truncation restores its parent's path on every exit. Owned diagnostic
+strings are constructed before sibling traversal can change the scratch path.
+
+Existing behavioral tests were reused; no timing/allocation threshold or new
+benchmark was introduced. These results concern this validation walk; other
+construction phases retain their own costs.