v4.4.0

Wave-3 implementation (leased to and delivered by the fleet's HDB session) and
round-3 declarative-partitioning Stage 0:

• PARTITION BY support (Stage 0) — PostgreSQL declarative-partitioning DDL
  is now accepted: CREATE TABLE … PARTITION BY RANGE/LIST/HASH parents
  (including multi-column, expression, and opclass keys), CREATE TABLE … PARTITION OF … FOR VALUES/DEFAULT children (columns cloned from the
  parent), and ATTACH/DETACH PARTITION as accepted no-ops. DROP TABLE parent cascades to its partition children (PG parity);
  pg_class.relpartbound is present (NULL). Stage-0 semantics: each child
  is an independent table — INSERT into the parent is not routed and SELECT
  from the parent does not union children yet (Stage 1). Measured on the
  PG regression corpus: +1,427 statements flip to passing.
• Version-copy elision — new [storage] elide_latest_version (default
  off): the latest row version lives only in data:, cutting single-INSERT
  version-write volume from 65% to 41% of bytes. One-way door: once
  enabled on a data dir, downgrade requires dump/restore.
• Statement retry on write conflicts — [locks] statement_retry_max
  (default 0 = off) auto-retries autocommit statements that hit the typed
  SQLSTATE 40001 write conflict; backoff knobs included.
• Snapshot schema evolution — [storage] snapshot_schema_evolution now
  defaults to "null_pad": reads through a snapshot taken before an ALTER TABLE ADD/DROP COLUMN return isolation-correct NULL-padded/truncated rows
  instead of erroring. Set "strict" to restore the previous error behavior.
• [locks] timeout_ms is now genuinely wired to the lock manager
  (previously orphaned); default 1000 preserves the prior effective bound.
• Fix (durability): the fast-INSERT row counter is flushed at clean
  shutdown — prevents silent row overwrites on reopen after short sessions in
  relaxed-WAL mode (crash-path reseed tracked separately).
• COPY constraint batching: ART maintenance batched per-table; CHECK
  expressions evaluated via a batched path (constrained-COPY follow-up from
  the Wave-3 measurements).