Housekeeping: migrate off deprecated TopologyGraph → BRepGraph. Closes #37. No behaviour change — pure rename, underlying type unchanged.
OCCTSwift renamed TopologyGraph → BRepGraph (too close to TopoDS, caused naming confusion — SecondMouseAU/OCCTSwift#333, shipped v1.15.0) and left a deprecated typealias in place. Mechanical rename across every reference in this repo (Sources/OCCTSwiftAIS/{Remap,InteractiveContext,InteractiveObject}.swift, four test files) and every doc naming the type in a current code snippet (SPEC.md, README.md, getting-started guide, one cookbook page, two reference pages) — the changelog's own history is left as-written.
Dependencies: OCCTSwiftTools floor raised 1.6.0 → 1.6.1, which itself re-pins to OCCTSwift >= 1.15.0 (SecondMouseAU/OCCTSwiftTools#46) — required now that this repo names BRepGraph directly, so a consumer without a local sibling checkout can't resolve an older OCCTSwift where BRepGraph doesn't exist yet.
Tests: 193 across 17 suites, all green, zero deprecation warnings (was ~30+ across the build).
Full changelog: https://github.com/SecondMouseAU/OCCTSwiftAIS/blob/main/docs/CHANGELOG.md