Summary

Closes #6167

Adds versioned feature view read/write support to the SnowflakeOnlineStore, following the pattern already established in SqliteOnlineStore, MySQLOnlineStore, PostgreSQLOnlineStore, DynamoDBOnlineStore, RedisOnlineStore, and MilvusOnlineStore.

What changed

snowflake.py

• Added _snowflake_table_name(project, table, enable_versioning) helper that returns "[online-transient] {project}_{name}" where name gains a _v{N} suffix when enable_online_feature_view_versioning is enabled and the feature view has a non-zero version.
• All four write/read paths (online_write_batch, online_read, update, teardown) now call this helper instead of hardcoding f"[online-transient] {config.project}_{table.name}".

online_store.py

• Added SnowflakeOnlineStore to the supported-types list in _check_versioned_read_support, so versioned reads no longer raise VersionedOnlineReadNotSupported.

New test file

• tests/unit/infra/online_store/test_snowflake_versioning.py — 10 unit tests covering: no versioning, versioning disabled with a version set, versioning enabled with no version, version number suffix, version zero (no suffix), projection tag priority, projection tag zero, two different versions produce different names, and _check_versioned_read_support with/without a version tag.
• Uses module-level stubs for cryptography, snowflake.connector, and tenacity so the tests run without the optional feast[snowflake] extras.

Reference

• Reference implementation: sdk/python/feast/infra/online_stores/sqlite.py
• Linked issue: Add feature view versioning support to Snowflake online store #6167 (part of Improved feature view and model versioning #2728)

Test plan

• python -m pytest sdk/python/tests/unit/infra/online_store/test_snowflake_versioning.py — 10/10 passed locally
• ruff format --check and ruff check — clean on all modified files
• Existing Snowflake table name behaviour is unchanged when enable_online_feature_view_versioning = False (the default)