Separate validation commands from tree checks

docs/roadmap/implementation.md

@@ -50,7 +50,7 @@ the agent policy; an intermediate compilation dependency is recorded accurately.
 | 12 | A08 | Complete — redirect boundary, origin authorization, cycle, and delivery outcome tests passed. |
 | 13 | A09 | Complete — bounded reads, size and digest mismatches, stream failures, cancellation, reconciliation, and public prebuilt delivery checks passed. |
 | 14 | A10 | Complete — bounded and full capture, forwarding, error identity, concurrency, and benchmark modes passed. |
-| 15 | A13 | Pending |
+| 15 | A13 | Complete — validation ordering, scope, tree lifecycle, diagnostics, and public callback checks passed. |
 | 16 | A15 | Pending |
 | 17 | Remaining A19, A20 | Pending |
 | 18 | A11, A17: assessment only | Pending |

internal/validation/validation.go

@@ -71,7 +71,7 @@ func (request Request) ReadCandidateTree(ctx context.Context) (*CandidateTree, e
 }
 
 // Run executes shared validation for the captured candidate.
-func Run(ctx context.Context, request Request) (result error) {
+func Run(ctx context.Context, request Request) error {
 	if request.Settings.FileSize != nil && request.Settings.FileSize.LimitBytes != nil && *request.Settings.FileSize.LimitBytes < 0 {
 		return &Failure{
 			Check:    FileSize,
@@ -89,6 +89,13 @@ func Run(ctx context.Context, request Request) (result error) {
 			}
 		}
 	}
+	if err := runGoChecks(ctx, request); err != nil {
+		return err
+	}
+	return runTreeChecks(ctx, request)
+}
+
+func runGoChecks(ctx context.Context, request Request) error {
 	goDirectory := request.ModuleDir
 	if goDirectory == "" {
 		goDirectory = request.RepositoryDir
@@ -134,6 +141,10 @@ func Run(ctx context.Context, request Request) (result error) {
 			}
 		}
 	}
+	return nil
+}
+
+func runTreeChecks(ctx context.Context, request Request) (result error) {
 	needsSharedSelection := len(request.Settings.SharedFiles) != 0
 	if request.Settings.GoFormat || request.Settings.ModuleDistribution.WorkspaceFiles || request.Settings.ModuleDistribution.LocalReplacements || request.Settings.FileSize != nil || request.Settings.Markdown != nil || needsSharedSelection || len(request.Settings.ForbiddenFiles) != 0 {
 		tree, err := request.ReadCandidateTree(ctx)