Promote bounds for nested evolved fields

[osipovartem]

Summary

• retain the O(1) field-ID lookup for top-level manifest bounds
• fall back to recursive struct/list/map lookup for nested primitive field IDs
• verify nested int -> long lower and upper bound promotion

Why

Iceberg metrics may be keyed by nested primitive field IDs. After another engine evolves a nested field, a Rustice append can rewrite its existing manifest entries under the widened schema. The top-level-only lookup added in #85 would leave those old bounds unconverted.

This runs only during manifest metadata rewrites; the normal top-level path remains a hash-map lookup and query row processing is unchanged.

Validation

• cargo +1.95.0 test -p iceberg-rust-spec promotes_bounds_to_the_manifest_schema -- --nocapture
• cargo +1.95.0 check -p iceberg-rust
• cargo +1.95.0 clippy -p iceberg-rust-spec -p iceberg-rust --all-targets -- -D warnings

Generic upstream version: JanKaul#410