[ZENOTME]

Purpose

Expose existing TableWrite::close() through the C API for explicit cleanup. Closes #1302.

Brief change log

Add paimon_table_write_close() using existing C binding conventions. Prepared messages remain caller-owned; free the handle separately.

Tests

Reuse test_write_commit_read_roundtrip: close the writer before committing its prepared messages, then verify the existing readback. No new fixture. Formatting checks pass.

API and Format

One additive C function; no storage format changes.

Documentation

Rustdoc describes ownership and handle lifetime.

[ZENOTME]

thread 'io::cache::disk::shared::tests::batch_download_locks_deduplicate_and_skip_busy_stripes' (14679) panicked at crates/paimon/src/io/cache/shared.rs:1180:9:
assertion `left == right` failed
  left: 0
 right: 2

Looks like unrelatd failure

[QuakeWang]

thread 'io::cache::disk::shared::tests::batch_download_locks_deduplicate_and_skip_busy_stripes' (14679) panicked at crates/paimon/src/io/cache/shared.rs:1180:9:
assertion `left == right` failed
  left: 0
 right: 2

Looks like unrelatd failure

@ZENOTME The unit (ubuntu) failure is the #1218 cache-lock flake, fixed on main in d8b3b11 (#1314). This branch is older than that. Could you rebase on main and push?