feat: support rewrite manifest

[ZENOTME]

Which issue does this PR close?

• Closes #.

What changes are included in this PR?

Are these changes tested?

[Copilot]

Pull Request Overview

Adds support for manifest rewriting by registering a new integration test and extending the manifest model with hashing and a deleted-files check.

• Registers rewrite_manifest_test in the shared integration tests
• Derives Eq and Hash on key manifest structs/enums and adds has_deleted_files to ManifestFile

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
crates/integration_tests/tests/shared_tests/mod.rs	Added mod rewrite_manifest_test; to include the new test module
crates/iceberg/src/spec/manifest_list.rs	Derived Eq, Hash on ManifestFile, ManifestContentType, FieldSummary and added has_deleted_files method

Comments suppressed due to low confidence (2)

crates/iceberg/src/spec/manifest_list.rs:594

• Add unit tests for has_deleted_files covering cases where deleted_files_count is None, Some(0), and Some(>0) to verify correct behavior.

pub fn has_deleted_files(&self) -> bool {

crates/integration_tests/tests/shared_tests/mod.rs:34

• Ensure that rewrite_manifest_test.rs exists in crates/integration_tests/tests/shared_tests/ and is named correctly to avoid a missing-module compilation error.

mod rewrite_manifest_test;