[beinan]

Production compaction still retained table writer ownership while waiting up to 10 seconds for the global stats-writer lock. After #308, nine production commit-phase observations averaged 12.51 seconds despite file encoding already running outside ownership.

Finish successful prepared compactions durably before reopening a read handle and refreshing statistics. This releases the existing task/table keys through the normal completion transaction; it does not bypass fencing, drain guards, or dedicated publishers. Keep the caller's task and compaction permits through refresh to bound concurrency, and report its latency separately as stats_refresh. No-op preparations and failed publication/completion skip refresh. A crash after completion may omit the best-effort compaction counter update; scans still refresh table counts.

Validation: add an etcd-backed regression covering owned and legacy publication with a competing stats writer. The Compact must become Done and the next MergeWal must acquire the table while refresh is blocked; the local compaction permit remains occupied until refresh finishes. Validation passed locally: all 139 master library tests including the full etcd HA suite (0 failures); focused prepared-compaction tests 4/4; master Clippy all targets with warnings denied; formatting and diff whitespace checks. GitHub CI is running.