DoltLite 0.11.51

Native serialization, broader backup support, custom collations, and
reliability fixes.

SQLite compatibility

• Added native sqlite3_serialize() and sqlite3_deserialize(). Images preserve
  schema, data, branches, history, refs, and working sets.

• sqlite3_backup_*() now supports attached and in-memory databases.

• Custom collations work for expressions and unindexed columns. Custom-
  collated indexes remain unsupported.

• All wal_checkpoint modes are accepted and mapped to chunk-store garbage
  collection.

Reliability

• Restored TLS 1.3 HTTPS support in released amalgamations while keeping TLS
  stripped from remotes-disabled builds.

• Rebases can survive reopen on dirty branches without losing uncommitted
  changes.

• Fixed exclusive range scans around extended numeric keys and pending
  mutations.

Benchmark / int-keys (100K rows, Linux x64)

File-Backed

Reads

Test	SQLite (us)	DoltLite (us)	Multiplier
oltp_point_select	84,822	37,809	0.45
oltp_range_select	15,721	10,430	0.66
oltp_sum_range	15,003	10,266	0.68
oltp_order_range	2,950	2,488	0.84
oltp_distinct_range	3,776	3,317	0.88
oltp_index_scan	10,104	5,860	0.58
select_random_points	15,790	10,703	0.68
select_random_ranges	9,100	4,868	0.53
covering_index_scan	10,252	5,249	0.51
groupby_scan	25,940	26,738	1.03
index_join	8,414	7,624	0.91
index_join_scan	3,580	3,987	1.11
types_table_scan	866,856	923,986	1.07
table_scan	1,002,516	1,013,149	1.01
oltp_read_only	177,473	111,595	0.63
Average			0.77

Writes

Test	SQLite (us)	DoltLite (us)	Multiplier
oltp_bulk_insert	200,151	261,101	1.30
oltp_insert	176,210	35,188	0.20
oltp_update_index	258,791	140,827	0.54
oltp_update_non_index	198,501	123,421	0.62
oltp_delete_insert	121,589	109,752	0.90
oltp_write_only	232,404	77,138	0.33
types_delete_insert	139,389	199,747	1.43
oltp_read_write	126,907	133,369	1.05
Average			0.80

100000 rows, median of 5 paired invocations per test; autocommit writes use 9, workload-only timing via host monotonic clock when available.