Setting `legacy_alter_table` works in shell but not in sqld

The legacy_alter_table pragma is required to reliably implement the suggested procedure for other kinds of schema changes without manually tracking views. Unfortunately, setting this pragma fails in Turso. I thought that this may perhaps be caused by compile-time options disabling legacy pragmas, but it's available in libsql-sqlite3:

$ ./libsql-sqlite3/libsql
-- Loading resources from /home/simon/.sqliterc
libSQL version 0.2.3 (based on SQLite version 3.44.0) 2023-11-01 11:23:50
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
libsql> pragma legacy_alter_table = 1;
libsql> .q

With a sqld build that should use the same sqlite3 build, it doesn't work:

$ ./target/debug/sqld &
$ turso db shell http://127.0.0.1:8080
Connected to http://127.0.0.1:8080

Welcome to Turso SQL shell!

Type ".quit" to exit the shell and ".help" to list all available commands.

→  pragma legacy_alter_table = 1;
Error: failed to execute SQL: pragma legacy_alter_table = 1;
SQL string could not be parsed: unsupported statement: pragma legacy_alter_table = 1

Reproduce the failure by running sqld and issuing pragma legacy_alter_table = 1; through turso db shell, then compare it with the libsql CLI behavior shown in the issue. Trace how sqld parses and executes PRAGMA statements. Done means the pragma is accepted and executes successfully through sqld.