IX4: the indexer names the trunk main once

trunkLike takes TrunkBranch where it named the string again, so the first watched branch changes in one place.

Builds: design 47 G §7, A-93

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

modules/mesh-delivery-indexer/internal/index/candidates.go

@@ -47,7 +47,7 @@ type Store interface {
 
 // trunkLike are the branches that are no group: a pull request from one is nobody's delivery group (the rule of
 // mesh-catalog modules/mesh-delivery/cmd/mesh-delivery/holder.go:321).
-var trunkLike = map[string]bool{"main": true, "master": true, "trunk": true, "": true}
+var trunkLike = map[string]bool{TrunkBranch: true, "master": true, "trunk": true, "": true}
 
 // writeTries bounds the reads again after a conflict; a message that still conflicts is left to the server to deliver again.
 const writeTries = 8

modules/mesh-delivery-indexer/internal/index/trunk_named_test.go

@@ -0,0 +1,37 @@
+package index
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// A-93, design 47 G §7: the trunk `main` is named once in the indexer, as TrunkBranch; no other non-test source of the module holds the
+// string, so the first watched branch changes in one place.
+func TestTheTrunkIsNamedOnceInTheIndexer(t *testing.T) {
+	var named []string
+	for _, dir := range []string{".", "../../cmd/mesh-delivery-indexer", "../judge"} {
+		files, err := filepath.Glob(filepath.Join(dir, "*.go"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, f := range files {
+			if strings.HasSuffix(f, "_test.go") {
+				continue
+			}
+			src, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _, line := range strings.Split(string(src), "\n") {
+				if t := strings.TrimSpace(line); strings.Contains(line, `"main"`) && !strings.HasPrefix(t, "//") {
+					named = append(named, filepath.Base(f))
+				}
+			}
+		}
+	}
+	if len(named) != 1 {
+		t.Errorf(`"main" is named %d times in code (%v), want once: TrunkBranch`, len(named), named)
+	}
+}