Bridge: CCG GenerativeCapacity → CrossSerial Phenomena

Connects the formal proof that CCG is strictly more expressive than CFG (from GenerativeCapacity) to the empirical cross-serial dependency classification in Phenomena.WordOrder.CrossSerial.

Both layers now use the canonical Core.FormalLanguageType, so the agreement is definitional.

theorem CCG.GenerativeCapacity.Bridge.phenomenal_agrees_with_theory : Phenomena.WordOrder.CrossSerial.crossSerialRequires = Core.FormalLanguageType.mildlyContextSensitive

The phenomenal classification agrees with the theory-level result: both assign cross-serial dependencies to the mildly context-sensitive level.

Phenomena.WordOrder.CrossSerial.crossSerialRequires reduces to Core.FormalLanguageType.mildlyContextSensitive, matching the generative capacity established by CCG.GenerativeCapacity.ccg_exceeds_cfg.