feat: validate spawn group refs

Author: MikelCalvo

internal/minimal/factory_test.go

@@ -3148,7 +3148,7 @@ func TestNewGameRuntimeExportsSpawnGroupsInContentBundle(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unexpected game runtime error: %v", err)
 	}
-	if _, ok := runtime.registerStaticActorWithInteractionCombatProfileAndSpawnGroupRef("Practice Wolf", 3, 1200, 2200, 101, "", "", worldruntime.StaticActorCombatProfilePracticeMob, "spawn:wolf:1"); !ok {
+	if _, ok := runtime.registerStaticActorWithInteractionCombatProfileAndSpawnGroupRef("Practice Wolf", 3, 1200, 2200, 101, "", "", worldruntime.StaticActorCombatProfilePracticeMob, "spawn.wolf_1"); !ok {
 		t.Fatal("expected spawn-backed static actor registration to succeed")
 	}
 
@@ -3163,7 +3163,7 @@ func TestNewGameRuntimeExportsSpawnGroupsInContentBundle(t *testing.T) {
 		t.Fatalf("expected one exported spawn group, got %+v", bundle.SpawnGroups)
 	}
 	spawnGroup := bundle.SpawnGroups[0]
-	if spawnGroup.Ref != "spawn:wolf:1" || spawnGroup.Name != "Practice Wolf" || spawnGroup.MapIndex != 3 || spawnGroup.X != 1200 || spawnGroup.Y != 2200 || spawnGroup.RaceNum != 101 || spawnGroup.CombatProfile != worldruntime.StaticActorCombatProfilePracticeMob {
+	if spawnGroup.Ref != "spawn.wolf_1" || spawnGroup.Name != "Practice Wolf" || spawnGroup.MapIndex != 3 || spawnGroup.X != 1200 || spawnGroup.Y != 2200 || spawnGroup.RaceNum != 101 || spawnGroup.CombatProfile != worldruntime.StaticActorCombatProfilePracticeMob {
 		t.Fatalf("unexpected exported spawn group: %+v", spawnGroup)
 	}
 }

internal/worldruntime/non_player_directory.go

@@ -162,7 +162,40 @@ func ValidStaticActorCombatProfile(profile string) bool {
 }
 
 func ValidStaticActorSpawnGroupRef(ref string) bool {
-	return ref == strings.TrimSpace(ref)
+	if ref == "" {
+		return true
+	}
+	if ref != strings.TrimSpace(ref) {
+		return false
+	}
+	segments := strings.Split(ref, ".")
+	if len(segments) < 2 {
+		return false
+	}
+	for _, segment := range segments {
+		if !validSpawnGroupRefSegment(segment) {
+			return false
+		}
+	}
+	return true
+}
+
+func validSpawnGroupRefSegment(segment string) bool {
+	if segment == "" {
+		return false
+	}
+	first := segment[0]
+	if first < 'a' || first > 'z' {
+		return false
+	}
+	for i := 1; i < len(segment); i++ {
+		c := segment[i]
+		if (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '_' {
+			continue
+		}
+		return false
+	}
+	return true
 }
 
 func sortStaticEntities(actors []StaticEntity) {

internal/worldruntime/non_player_directory_test.go

@@ -414,6 +414,30 @@ func TestNonPlayerDirectoryPreservesSpawnGroupRefOnRegisterAndUpdate(t *testing.
 	}
 }
 
+func TestNonPlayerDirectoryRejectsNonCanonicalSpawnGroupRef(t *testing.T) {
+	for name, ref := range map[string]string{
+		"blank segment":      "practice..mob",
+		"uppercase segment":  "practice.Mob",
+		"hyphenated segment": "practice-mob",
+		"leading digit":      "1practice.mob",
+		"missing namespace":  "practice_mob",
+	} {
+		t.Run(name, func(t *testing.T) {
+			directory := NewNonPlayerDirectory()
+			actor := StaticEntity{
+				Entity:        Entity{ID: 14, Kind: EntityKindStaticActor, Name: "PracticeMobAlpha"},
+				Position:      NewPosition(42, 1800, 2900),
+				RaceNum:       101,
+				CombatProfile: StaticActorCombatProfilePracticeMob,
+				SpawnGroupRef: ref,
+			}
+			if directory.Register(actor) {
+				t.Fatalf("expected spawn-backed actor with ref %q to be rejected", ref)
+			}
+		})
+	}
+}
+
 func TestNonPlayerDirectoryRejectsStandaloneStaticActorDeathReward(t *testing.T) {
 	directory := NewNonPlayerDirectory()
 	actor := StaticEntity{

spec/protocol/content-spawn-groups-bootstrap.md

@@ -103,6 +103,8 @@ The first bootstrap spawn-group contract freezes these fields:
 - `ref`
   - stable authored identifier for the spawn group
   - unique within the bundle
+  - canonical dotted lowercase identifier made of at least two `[a-z][a-z0-9_]*` segments, for example `practice.mob_alpha`
+  - runtime import and static-actor snapshot validation reject non-canonical refs instead of preserving ambiguous authored ownership keys
   - this is the authored identity that future runtime respawn ownership binds to
 - `name`
   - required operator-friendly display label
@@ -190,7 +192,7 @@ What is **not** yet frozen here:
 ## Validation rules
 
 The first content contract should fail closed when:
-- `ref` is empty or duplicated
+- `ref` is empty, duplicated, or not in the canonical dotted lowercase form `[a-z][a-z0-9_]*(.[a-z][a-z0-9_]*)+`
 - `name` is empty after trimming whitespace
 - `map_index` is `0`
 - `race_num` is `0`