Release URSA 1.3.0 with route policies and CDXML schemes

[nbondarev-insilico]

Summary

• Release URSA 1.3.0 and score routes with public ChemCensor 1.4 against the U3 database.
• Add optional building-block matching and best-path selection policies.
• Export CDXML schemes named by benchmark structure ID.

Test plan

• uv run pytest (248 passed, 39 skipped)
• uv run pre-commit run --all-files on the changed files
• Scoring run downloaded ChemCensor-DB-U3.sqlite (5,559,713,792 bytes) and --prepare-cdxml-files wrote X404-1760-0042.cdxml and X404-1768-3704.cdxml