feat(html): add fluent entitlements context setters

Co-Authored-By: Virgil <virgil@lethean.io>

context.go

@@ -119,6 +119,19 @@ func (ctx *Context) SetService(svc Translator) *Context {
 	return ctx
 }
 
+// SetEntitlements updates the feature gate callback used by Entitled nodes and
+// returns the same context.
+// Example: ctx.SetEntitlements(func(feature string) bool { return feature == "premium" }).
+func (ctx *Context) SetEntitlements(entitlements func(feature string) bool) *Context {
+	if ctx == nil {
+		return nil
+	}
+
+	ensureContextDefaults(ctx)
+	ctx.Entitlements = entitlements
+	return ctx
+}
+
 // SetIdentity updates the context identity and returns the same context.
 // Example: ctx.SetIdentity("user-123").
 func (ctx *Context) SetIdentity(identity string) *Context {
@@ -188,6 +201,17 @@ func (ctx *Context) WithService(svc Translator) *Context {
 	return clone
 }
 
+// WithEntitlements returns a cloned context with a different feature gate callback.
+// Example: next := ctx.WithEntitlements(func(feature string) bool { return feature == "premium" }).
+func (ctx *Context) WithEntitlements(entitlements func(feature string) bool) *Context {
+	clone := ctx.Clone()
+	if clone == nil {
+		return nil
+	}
+	clone.SetEntitlements(entitlements)
+	return clone
+}
+
 // SetLocale updates the context locale and reapplies it to the active
 // translator.
 // Example: ctx.SetLocale("en-US").

context_test.go

@@ -96,6 +96,20 @@ func TestContext_SetService_ReappliesCurrentLocale(t *testing.T) {
 	}
 }
 
+func TestContext_SetEntitlements_UpdatesFeatureGate(t *testing.T) {
+	ctx := NewContext()
+
+	if got := ctx.SetEntitlements(func(feature string) bool { return feature == "premium" }); got != ctx {
+		t.Fatalf("SetEntitlements should return the same context")
+	}
+	if ctx.Entitlements == nil {
+		t.Fatal("SetEntitlements should store the callback")
+	}
+	if !ctx.Entitlements("premium") {
+		t.Fatal("SetEntitlements should preserve the requested callback")
+	}
+}
+
 func TestContext_SetIdentity_UpdatesIdentity(t *testing.T) {
 	ctx := NewContext()
 
@@ -258,6 +272,40 @@ func TestContext_WithServiceReturnsClonedContext(t *testing.T) {
 	}
 }
 
+func TestContext_WithEntitlementsReturnsClonedContext(t *testing.T) {
+	ctx := NewContext()
+	ctx.SetIdentity("user-001")
+	ctx.SetData("theme", "dark")
+	ctx.SetEntitlements(func(feature string) bool { return feature == "basic" })
+
+	next := ctx.WithEntitlements(func(feature string) bool { return feature == "premium" })
+
+	if next == ctx {
+		t.Fatal("WithEntitlements should return a cloned context")
+	}
+	if ctx.Entitlements == nil {
+		t.Fatal("WithEntitlements should not clear the original callback")
+	}
+	if !ctx.Entitlements("basic") {
+		t.Fatal("WithEntitlements should preserve the original callback")
+	}
+	if next.Entitlements == nil {
+		t.Fatal("WithEntitlements should store the new callback on the clone")
+	}
+	if next.Entitlements("basic") {
+		t.Fatal("WithEntitlements should replace the callback on the clone")
+	}
+	if !next.Entitlements("premium") {
+		t.Fatal("WithEntitlements should preserve the new callback")
+	}
+	if got := next.Data["theme"]; got != "dark" {
+		t.Fatalf("WithEntitlements should preserve existing data on the clone, got %v", got)
+	}
+	if got := next.Identity; got != "user-001" {
+		t.Fatalf("WithEntitlements should preserve identity on the clone, got %q", got)
+	}
+}
+
 func TestContext_Setters_NilReceiver(t *testing.T) {
 	var ctx *Context
 
@@ -273,12 +321,18 @@ func TestContext_Setters_NilReceiver(t *testing.T) {
 	if got := ctx.SetService(&localeTranslator{}); got != nil {
 		t.Fatalf("nil Context.SetService should return nil, got %v", got)
 	}
+	if got := ctx.SetEntitlements(func(string) bool { return true }); got != nil {
+		t.Fatalf("nil Context.SetEntitlements should return nil, got %v", got)
+	}
 	if got := ctx.WithLocale("en-GB"); got != nil {
 		t.Fatalf("nil Context.WithLocale should return nil, got %v", got)
 	}
 	if got := ctx.WithService(&localeTranslator{}); got != nil {
 		t.Fatalf("nil Context.WithService should return nil, got %v", got)
 	}
+	if got := ctx.WithEntitlements(func(string) bool { return true }); got != nil {
+		t.Fatalf("nil Context.WithEntitlements should return nil, got %v", got)
+	}
 }
 
 func TestText_RenderFallsBackToDefaultTranslator(t *testing.T) {