Cleanup canonical imports and split data integration from h5_kit

[xiao312]

Summary

• switch remaining repo-internal code paths to canonical package imports where practical
• update canonical CLI internals to use cases instead of df_interface
• add dfode_kit.data.integration as the canonical home for reactor/model/integration helpers
• reduce dfode_kit.data_operations.h5_kit to a compatibility shim
• update root/data package re-exports to point at canonical modules
• update tutorial .py files to import canonical data APIs
• add lightweight shim tests for the extracted HDF5 surface

Verification

• targeted pytest slice passed
• make verify passed
• make docs-build passed