Migrate existing rules to PSSA2

PSSA2 should support most or all existing PSSA rules. Some rules may be inappropriate for continued use and others may need to be expanded, but gradual migration of rules should be possible.

Dependencies on Helper methods should be replaced with general purpose implementations that live under the appropriate class and injected into rules at instantiation time.

Some rules may need refinement or improvement, particularly in name or implementation. When this is done, a mechanism should be provided to improve compatibility.

先盤點現有的 PSSA 規則及其對 Helper methods 的相依性，然後比較 PSSA2 如何具現化規則。定義哪些規則可以遷移、通用實作應放在哪裡，以及如何為已重新命名或細化的規則保留相容性。