Implements SPECIFICATION.md §6 BCF→ifc:// direction: parse a BCF 3.0
REST viewpoint dict (camera, clips, selection/visibility) and apply it
to a base IfcUrl to produce an ifc:// URL string.
IfcUrl.to_string() serialises any IfcUrl back to a valid ifc:// URL,
enabling round-trip parse→to_string for all URL forms.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- url.py: preserve non-standard ports in host field; ifc://host:3000/...
now correctly generates https://host:3000/... rather than dropping :3000
- git.py: fall back from https to http on clone/fetch failure, enabling
local Gitea instances running on plain HTTP; inject tokens into http://
URLs as well as https://; extract _clone_bare() helper
- tests/test_url.py: three new tests for port preservation in host,
git_remote_url with non-standard HTTPS port, and SSH with non-standard port
