[kvlonge]

Why

Native planner flows still rebuilt Python graph and model-map containers only to read them back. Keep that data native through planning and make this ownership fix available in a patch release.

Changes

• Traverse retained native graphs for deferred clones and source freshness.
• Use native model lookup for old-name planning and column-cursor redirects.
• Share clone traversal with public callback APIs while preserving their Python semantics.
• Document intentional Python boundaries and lower crossing budgets.

Verification

• 1,158 targeted planner, freshness and CLI unit/integration tests passed.
• 220 Rust core tests and 1,000 seeded graph-reference comparisons passed.
• uv sync --all-extras and the exact make check-ci target passed; independent review found no blockers.
• Ownership-only cleanup: existing DuckDB migration/planner cases cover the affected shapes; no new SQL, data or lifecycle edge case requires a DuckShop fixture.