[XiaoHongbo-Hope]

Purpose

After #1259 seeds the schema cache from the REST catalog response, $schemas.update_time can report the time the client reconstructed the schema instead of its persisted timestamp. Python/native parity tests fail even on empty tables.

Read enumerated schema files through a fresh file-backed manager in list_all. Keep catalog-resolved schemas available to ordinary schema lookups, including catalogs without schema files. Add a regression with different persisted and catalog-resolved timestamps.

Tests

• Reproduced the three $schemas parity failures on Apache Paimon master 1418eb504e with Rust 74834711, including empty tables and branch reads.
• Added a regression proving listing uses the persisted timestamp while ordinary schema lookup retains the catalog cache.
• cargo test --release -p paimon --lib table::schema_manager::tests: 8 passed, including the new regression.
• cargo fmt --all -- --check and git diff --check passed.
• The full Python/native suite has not yet been rerun against a rebuilt extension containing this fix.

Companion Python fixture fixes: apache/paimon#10900. Those fix the other 15 Native CI failures without changing schema parity assertions.

[JingsongLi]

+1