feat: generate PolyAPI SDK; support shared package imports

EN #5300 Update to run secure poly setup and generate (#4)

* EN add poly setup and generate step

* EN create package folders for schemas, tabi, and vari

* EN update py to v3.13

* EN #5300 enable secure poly setup and generate

* EN #5300 update env var names to match TS client

* EN re-order steps so generated bits don't get clobbered by cache

* EN revert db6c78bb0118e4f878338bddf3b3ca603455a24a

* EN scope down cache dir

* EN make cache key more unique for multi env deployments

* EN also cache deployments_revision