Add CycloneDX SBOM for C extensions

Includes all 8 C extension modules, 3 vendored thirdparty libraries
(raqm 0.10.3, fribidi-shim, pythoncapi_compat), and 13 optional native
library dependencies with encoded dependency relationships.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: aclark4life