feat: add deletion vector compaction execution

[wirybeaver]

Summary

• add a narrow CompactionExecutor API that consumes snapshot-bound planner groups and rewrites live rows through FileScanTaskReader and DataWriter
• refresh before writing, reject stale plans, and use ValidateFromSnapshot(source_snapshot_id) to prevent concurrent deletes from being resurrected
• atomically replace all planned data files while removing superseded file-scoped Parquet position-delete and deletion-vector entries
• preserve data sequence numbers and v3 row lineage, including files written before a v2-to-v3 table upgrade
• validate source-file uniqueness before writing and retain shared Puffin objects
• define FileIO::DeleteFile as idempotent for missing paths and enforce the contract in Arrow and test implementations, allowing the executor to own output paths before creation and safely clean up failures at any writer-construction stage while retaining real deletion failures
• rebuild the stack on final Ticket 04 commit 477a2ff, replay final Ticket 07 source 56ed503 exactly as 5e0c98b, and keep executor work in one commit

Closes #916.

Depends on #913, #914, #915, #918, and #919.

Test plan

• cmake --build build --target data_test compaction_planner_test arrow_test -j3 — passed
• ./build/src/iceberg/test/data_test --gtest_filter='CompactionExecutor*' — 12 passed
• ./build/src/iceberg/test/data_test — 192 passed
• ./build/src/iceberg/test/compaction_planner_test — 18 passed
• ./build/src/iceberg/test/arrow_test — 83 passed
• pre-commit run -a — all hooks passed

Executor coverage includes physical row removal, no dangling delete-manifest entries, shared Puffin safety, duplicate-plan rejection, stale-plan rejection, multi-file/multi-group atomicity, cleanup failure and retry, writer failure before creation, OutputFile::Create failure before materialization, failure after file creation, executor reuse, commit-state-unknown ownership, file-scoped Parquet delete removal, and upgraded-table row lineage. FileIO coverage verifies idempotent deletion of missing files for Arrow and the standard test implementation.