fix(database): make v2->v3 chatlog migration deterministic and FK-safe

_migrate_to_v3 deduplicated duplicate archive_id rows with a bare-column
GROUP BY, which lets SQLite keep an arbitrary row per group (in practice the
older row, dropping the latest), and copied rows with SELECT *, which relies
on positional column matching between the v2 and v3 schemas.

- Keep MAX(id) per archive_id group ("latest insert wins") instead of
  GROUP BY's implementation-defined pick.
- Sweep replaces_db_id / replaced_by_db_id after dedupe, NULLing references
  to dropped rows so the migrated table carries no dangling XEP-0308 (LMC)
  links (the "Broken LMC reference" condition verify_integrity flags).
- List columns explicitly instead of SELECT * so the copy cannot mis-bind,
  and note at the schema that column changes must be mirrored here.

Refs #128

src/database_sqlite.c

@@ -178,6 +178,9 @@ _sqlite_init(ProfAccount* account)
     //   replaced_by_db_id Inverse FK: id of the most recent correction.
     //                     Maintained by the AFTER INSERT trigger below so
     //                     readers can follow the chain forward in O(1).
+    //
+    // NOTE: any change to these columns (add/remove/reorder) must be mirrored
+    // in `_migrate_to_v3`, which copies rows via an explicit column list.
     const char* query = "CREATE TABLE IF NOT EXISTS `ChatLogs` ("
                         "`id` INTEGER PRIMARY KEY AUTOINCREMENT, "
                         "`from_jid` TEXT NOT NULL, "
@@ -865,11 +868,37 @@ _migrate_to_v3(void)
         "`replaces_db_id` INTEGER, "
         "`replaced_by_db_id` INTEGER)",
 
+        // Copy rows into the deduped table. Columns are listed explicitly
+        // (instead of `SELECT *`) so the migration cannot silently mis-bind
+        // should the v2/v3 column order ever diverge — keep this list in sync
+        // with the `ChatLogs_v3_migration` schema above and the live `ChatLogs`
+        // schema. For duplicate `archive_id` groups (MAM rebroadcasts) keep the
+        // highest `id` deterministically ("latest insert wins") rather than
+        // GROUP BY's implementation-defined arbitrary pick.
         "INSERT INTO `ChatLogs_v3_migration` "
-        "SELECT * FROM `ChatLogs` "
-        "WHERE `archive_id` IS NULL "
+        "(`id`, `from_jid`, `to_jid`, `from_resource`, `to_resource`, `message`, "
+        "`timestamp`, `type`, `stanza_id`, `archive_id`, `encryption`, "
+        "`marked_read`, `replace_id`, `replaces_db_id`, `replaced_by_db_id`) "
+        "SELECT `id`, `from_jid`, `to_jid`, `from_resource`, `to_resource`, `message`, "
+        "`timestamp`, `type`, `stanza_id`, `archive_id`, `encryption`, "
+        "`marked_read`, `replace_id`, `replaces_db_id`, `replaced_by_db_id` "
+        "FROM `ChatLogs` WHERE `archive_id` IS NULL "
         "UNION ALL "
-        "SELECT * FROM (SELECT * FROM `ChatLogs` WHERE `archive_id` IS NOT NULL GROUP BY `archive_id`)",
+        "SELECT `id`, `from_jid`, `to_jid`, `from_resource`, `to_resource`, `message`, "
+        "`timestamp`, `type`, `stanza_id`, `archive_id`, `encryption`, "
+        "`marked_read`, `replace_id`, `replaces_db_id`, `replaced_by_db_id` "
+        "FROM `ChatLogs` WHERE `archive_id` IS NOT NULL "
+        "AND `id` IN (SELECT MAX(`id`) FROM `ChatLogs` WHERE `archive_id` IS NOT NULL GROUP BY `archive_id`)",
+
+        // Dropping duplicate rows above can leave the surviving rows' correction
+        // back-links pointing at ids that no longer exist. NULL them out so the
+        // XEP-0308 (LMC) chain carries no dangling local foreign keys.
+        "UPDATE `ChatLogs_v3_migration` SET `replaces_db_id` = NULL "
+        "WHERE `replaces_db_id` IS NOT NULL "
+        "AND `replaces_db_id` NOT IN (SELECT `id` FROM `ChatLogs_v3_migration`)",
+        "UPDATE `ChatLogs_v3_migration` SET `replaced_by_db_id` = NULL "
+        "WHERE `replaced_by_db_id` IS NOT NULL "
+        "AND `replaced_by_db_id` NOT IN (SELECT `id` FROM `ChatLogs_v3_migration`)",
 
         "DROP TABLE `ChatLogs` ",
         "ALTER TABLE `ChatLogs_v3_migration` RENAME TO `ChatLogs` ",