feat(table): add manifest compaction API

[jianguotian]

Purpose

Expose explicit manifest maintenance before making that maintenance force one global sort. This mirrors the pre-full-sort compact_manifest behavior in Java Paimon.

Changes

• add TableCommit::compact_manifests()
• force maintenance compaction thresholds without mutating stored table options
• commit a metadata-only COMPACT snapshot only when the manifest set changes
• preserve record counts, index manifest, watermark, statistics, properties, and next RowID
• retry optimistic snapshot conflicts with the table's configured retry policy
• compact legacy unsorted manifests as well as the sorted path
• eliminate cross-manifest ADD/DELETE pairs and keep repeated maintenance idempotent

Merge order

Merge after #856. The next PR will make this API request an explicit global full sort, matching apache/paimon#9802.

Verification

• cargo fmt --check
• cargo test -p paimon --lib — 2,849 passed, 2 ignored
• cargo clippy -p paimon --lib --tests -- -D warnings -A clippy::unnecessary-cast
• dedicated tests for COMPACT snapshot publication, active-file preservation, delete elimination, empty delta manifests, and idempotence

Related Java work

• [flink][spark] Support manifest sort in compact_manifest paimon#9083
• Apache Paimon FileStoreCommit.compactManifest() / BatchTableCommit.compactManifests()