Construction resources

Enable the facade's resource feature to inspect and author the bounded IFC4/IFC4X3 construction-resource slice:

openbim-ifc = { git = "https://github.com/openbimrs/ifc.git", features = ["resource"] }

The API selects IFC4 or IFC4X3 from Model::header().schema; IFC2X3, missing, and ambiguous declarations return typed errors (IFC2X3 does not declare IfcConstructionResourceType, IfcResourceTime, or PredefinedType on two occurrence subtypes, so there is no normative behavior to project). Attribute slots come from the bundled IFC4 ADD2 TC1 or IFC4X3 ADD2 schema rather than fixed indices.

use ifc::resource::{
    AllocationDraft, NestingDraft, ResourceDraft, ResourceEditor, ResourceKind,
    ResourceTimeDraft, ResourceView,
};
use ifc::Model;

let mut model = Model::new();
model.header_mut().schema.push("IFC4".into());

let (crew, carpenter, usage, allocation) = {
    let mut editor = ResourceEditor::for_model(&mut model)?;
    let usage = editor.create_time(
        ResourceTimeDraft::new()
            .name("Day shift")
            .schedule_work("PT8H")
            .schedule_usage(1.0),
    )?;
    let crew = editor.create_resource(
        ResourceDraft::new(ResourceKind::Crew, "2O2Fr$t4X7Zf8NOew3FLOH")
            .name("Envelope crew")
            .predefined_type("OFFICE")
            .usage(usage),
    )?;
    let carpenter = editor.create_resource(
        ResourceDraft::new(ResourceKind::Labor, "1O2Fr$t4X7Zf8NOew3FLOH")
            .name("Carpenter")
            .predefined_type("CARPENTRY"),
    )?;
    let allocation = editor.create_allocation(
        AllocationDraft::new("3O2Fr$t4X7Zf8NOew3FLOH", carpenter, vec![crew])
            .related_objects_type("RESOURCE"),
    )?;
    editor.create_nesting(NestingDraft::new(
        "0O2Fr$t4X7Zf8NOew3FLOH",
        crew,
        vec![carpenter],
    ))?;
    (crew, carpenter, usage, allocation)
};

let resources = ResourceView::for_model(&model)?;
assert_eq!(resources.allocation(allocation)?.related_objects_type(), Some("RESOURCE"));
assert_eq!(resources.resource(carpenter)?.name()?, Some("Carpenter"));
assert_eq!(resources.resource_time(usage)?.schedule_work()?, Some("PT8H"));
assert_eq!(resources.descendants(crew, Default::default())?, vec![carpenter]);
# Ok::<(), ifc::resource::ResourceError>(())

Invalid schema headers, references, enum members, ratios, aggregates, duplicate GlobalId values, mismatched IfcRelAssigns.RelatedObjectsType categories, second resource parents, cycle creation, malformed authored graphs, and exhausted traversal budgets return typed ResourceError values. Rejected drafts leave model length and revision unchanged.

What this does not do

The crate preserves and validates authored resource data. It does not level resources, calculate duration/cost/quantity, interpret work calendars, solve logistics, or manufacture allocation from schedule/cost data. IFC2X3 semantics are not a public capability (the schema does not declare the entities this crate projects).