test(01-04): cover config, lifecycle, services, events and context

- Table-driven compass precedence, malformed YAML, snake_case env and concurrent reads
- Party duplicate/missing/cycle, reordered manifest, HasConfig/HasCommands discovery
- Isolated backpack services, festival panic payload omission, towel nested isolation

towel/context_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"strings"
+	"sync"
 	"testing"
 )
 
@@ -33,6 +34,85 @@ func TestContextAccessorsRoundTrip(t *testing.T) {
 	}
 }
 
+func TestNestedContextIsolation(t *testing.T) {
+	parent := WithActor(context.Background(), "parent")
+	parent = WithOrganization(parent, "org-parent")
+	child := WithActor(parent, "child")
+	child = WithCollection(child, "col-child")
+	child = WithLocale(child, "pl")
+
+	if got, ok := Actor(parent); !ok || got != "parent" {
+		t.Fatalf("parent Actor mutated: (%q, %v)", got, ok)
+	}
+	if got, ok := Actor(child); !ok || got != "child" {
+		t.Fatalf("child Actor = (%q, %v)", got, ok)
+	}
+	if got, ok := Organization(child); !ok || got != "org-parent" {
+		t.Fatalf("child should inherit organization, got (%q, %v)", got, ok)
+	}
+	if _, ok := Collection(parent); ok {
+		t.Fatal("collection leaked to parent")
+	}
+	if _, ok := Locale(parent); ok {
+		t.Fatal("locale leaked to parent")
+	}
+	if got, ok := Collection(child); !ok || got != "col-child" {
+		t.Fatalf("child Collection = (%q, %v)", got, ok)
+	}
+}
+
+func TestNilContextAccessors(t *testing.T) {
+	if _, ok := Actor(nil); ok {
+		t.Fatal("Actor(nil) should be absent")
+	}
+	if _, ok := Organization(nil); ok {
+		t.Fatal("Organization(nil) should be absent")
+	}
+	if _, ok := Collection(nil); ok {
+		t.Fatal("Collection(nil) should be absent")
+	}
+	if _, ok := Locale(nil); ok {
+		t.Fatal("Locale(nil) should be absent")
+	}
+	ctx := WithActor(nil, "user-1")
+	if got, ok := Actor(ctx); !ok || got != "user-1" {
+		t.Fatalf("WithActor(nil) = (%q, %v)", got, ok)
+	}
+}
+
+func TestConcurrentContextAccessors(t *testing.T) {
+	ctx := WithActor(context.Background(), "user-1")
+	ctx = WithOrganization(ctx, "org-9")
+	ctx = WithCollection(ctx, "col-3")
+	ctx = WithLocale(ctx, "pl")
+	var wg sync.WaitGroup
+	for i := 0; i < 16; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for j := 0; j < 80; j++ {
+				if got, ok := Actor(ctx); !ok || got != "user-1" {
+					t.Errorf("Actor = (%q, %v)", got, ok)
+					return
+				}
+				if got, ok := Organization(ctx); !ok || got != "org-9" {
+					t.Errorf("Organization = (%q, %v)", got, ok)
+					return
+				}
+				if got, ok := Collection(ctx); !ok || got != "col-3" {
+					t.Errorf("Collection = (%q, %v)", got, ok)
+					return
+				}
+				if got, ok := Locale(ctx); !ok || got != "pl" {
+					t.Errorf("Locale = (%q, %v)", got, ok)
+					return
+				}
+			}
+		}()
+	}
+	wg.Wait()
+}
+
 func TestNoPackageGlobalRequestState(t *testing.T) {
 	entries, err := os.ReadDir(".")
 	if err != nil {