refactor(storage): split Python service responsibilities - #3592

Summary

Split the Python storage service into cohesive private backend, Episode, and Fact/query owners while retaining the public compatibility facade, dynamic monkeypatch seams, exact StorageTransfer callable identity, persistence behavior, and native storage authority.

Validation

• Full ./shifu check:source passed on exact head 4b814fd4f94b4dbd8a1e75292530a5b454561f22: 1195 passed, 11 declared skips, 0 failures.
• Python contract 40/40; upgrade 143/143; desktop 73/73.
• Ruff passed; mypy passed for 320 source files.
• Python structure blocking=0; code complexity, function-risk, semantic amplification, KFD, support-matrix, and documentation contracts passed.
• Independent native tracked review review-3342f46a169a62fc58b23cb5 returned fit with zero evidence requests or follow-ups.
• Portable seal: sha256:0ea21c5324c950a56de57c927cfda73df1d8752df89eef14868356d402d2dbf1.

Supersedes #3507, #3511, #3588, and #3589.

ADR delivery / release declaration

Evolution Map impact

Evolution impact: none

Governance risk check

• none of the above

Checklist

• Commits are signed off (DCO)