Fix 10: the indexer's source catch-up and trunk directories are answered in name order, not a map's

Kind: an order asserted or acted on that came from ranging a map.
Builds: design 47 G §15, §115, §362

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main_test.go

@@ -217,7 +217,7 @@ func TestTheSourceIsReadFromTheSeatAndASourceMovedDuringTheCatchUpIsReadAfterIt(
 	s.catchUp(context.Background())
 	// The trunk, then each other watched branch the seat lists (a name unescaped), then what was heard meanwhile once each,
 	// beta among them: main through the take-in, every other branch into its own revision (A-93).
-	want := []string{"read main", "apply main 4", "read ", "read beta", "branch beta 4", "read feat=2e1", "branch feat.1 4", "read main", "apply main 4", "read beta", "branch beta 4"}
+	want := []string{"read main", "apply main 4", "read ", "read beta", "branch beta 4", "read feat=2e1", "branch feat.1 4", "read beta", "branch beta 4", "read main", "apply main 4"}
 	if !reflect.DeepEqual(order, want) {
 		t.Errorf("order = %v, want %v", order, want)
 	}

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/named.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-checker/checkermsg"
 	"path"
+	"slices"
 	"strings"
 
 	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient"
@@ -110,6 +111,7 @@ func trunkVia(call toolCaller) func(ctx context.Context, repository, sha string)
 		for dir := range a.Trees {
 			dirs = append(dirs, dir)
 		}
+		slices.Sort(dirs) // a map's order is random: the directories are answered in name order
 		return dirs, nil
 	}
 }

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/named_test.go

@@ -83,7 +83,6 @@ func TestTheTrunkIsTheDirectoriesTheForgeListsTrees(t *testing.T) { // 1900/AC3
 	if err != nil {
 		t.Fatal(err)
 	}
-	slices.Sort(dirs)
 	if !slices.Equal(dirs, []string{"modules/a", "modules/b"}) {
 		t.Errorf("dirs = %v", dirs)
 	}

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/source.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"maps"
+	"slices"
 	"strings"
 	"sync"
 
@@ -71,7 +73,7 @@ func (s *sourceFollow) catchUp(ctx context.Context) {
 	branches := s.waiting
 	s.waiting = nil
 	s.mu.Unlock()
-	for branch := range branches {
+	for _, branch := range slices.Sorted(maps.Keys(branches)) { // a map's order is random: the branches are read in name order
 		s.take(ctx, branch)
 	}
 }