feat: add admin screens, permissions and navigation

Seven admin controllers in a "Studia BM" navigation group, guarded by
jz.bm.access_courses, jz.bm.access_schedule and jz.bm.access_materials,
with Polish and English labels. Date and time fields are checked by the
models before a save and answered as 422 on the field.

controllers/materials.go

@@ -0,0 +1,53 @@
+// Code generated by summer make. DO NOT EDIT.
+
+package controllers
+
+import (
+	"git.golem15.com/golem15/summercms/modules/cabana"
+	"git.golem15.com/golem15/summercms/modules/pact"
+	"git.golem15.com/jakub/sm-bm-plugin/models"
+)
+
+var (
+	_ pact.AdminController   = materialsAdmin{}
+	_ pact.AdminRecordSource = materialsAdmin{}
+	_ pact.AdminPermissioned = materialsAdmin{}
+)
+
+// materialsAdmin is the admin controller for materials.
+type materialsAdmin struct{ temporalHooks }
+
+func (materialsAdmin) ID() string        { return "jz.bm.materials" }
+func (materialsAdmin) ModelName() string { return "Material" }
+func (materialsAdmin) ConfigDir() string { return "controllers/materials" }
+
+// NewRecord returns the model the generic admin handlers query and fill.
+func (materialsAdmin) NewRecord() any { return &models.Material{} }
+
+// RequiredPermissions is checked before any schema or record is served.
+func (materialsAdmin) RequiredPermissions() []string {
+	return []string{PermMaterials}
+}
+
+// AdminFieldRelations binds the course picker and the tags.
+//
+// TODO: requires SummerCMS change. Materials carry their files as
+// system_files attachments (field "files"), but cabana has no file upload
+// form widget, so files are attached outside the admin form for now.
+func (materialsAdmin) AdminFieldRelations() []cabana.FieldRelationContract {
+	return []cabana.FieldRelationContract{
+		courseRelation("course_id"),
+		{
+			Field:             "tags",
+			Kind:              "belongsToMany",
+			NewRelated:        func() any { return &models.Tag{} },
+			NewPivot:          func() any { return &models.MaterialTag{} },
+			ParentForeignKey:  "material_id",
+			RelatedForeignKey: "tag_id",
+			LabelColumn:       "name",
+		},
+	}
+}
+
+// MaterialsController returns the jz.bm.materials admin controller.
+func MaterialsController() pact.AdminController { return materialsAdmin{} }