[python] Add PyPaimon maintenance operations

[HansiChan]

Purpose

This PR adds native PyPaimon APIs and CLI commands for table maintenance and snapshot inspection.

Changes

• Add SnapshotManager.list_snapshots() and extend table snapshot CLI with --id, --earliest, --time-millis, and --all.
• Add table.new_maintenance() with compact(partition=None) and rescale_bucket(bucket_num, partition=None).
• Add CLI commands for table compact and table rescale.
• Document the new snapshot and maintenance APIs.

Native Python maintenance currently rejects row tracking, data evolution, and deletion-vector tables because those modes require extra metadata handling beyond a plain data rewrite.

Tests

• PYTHONPATH=. python -m pytest pypaimon/tests/table/maintenance_test.py
• PYTHONPATH=. python -m pytest pypaimon/tests/cli_table_test.py -k snapshot
• python -m flake8 --config=paimon-python/dev/cfg.ini paimon-python/pypaimon/cli/cli_table.py paimon-python/pypaimon/common/json_util.py paimon-python/pypaimon/snapshot/snapshot_manager.py paimon-python/pypaimon/table/file_store_table.py paimon-python/pypaimon/table/maintenance.py paimon-python/pypaimon/write/file_store_commit.py paimon-python/pypaimon/write/table_commit.py paimon-python/pypaimon/tests/cli_table_test.py paimon-python/pypaimon/tests/table/maintenance_test.py