sqlite: add serialize() and deserialize() to DatabaseSync

[thisalihassan]

What is the problem this feature will solve?

There is currently no way to extract a database's contents as a binary buffer or load a database from one. Users may use this for snapshot, clone, transfer, etc. Popular libraries like better-sqlite3 expose db.serialize() and new Database(buffer) for this purpose.

What is the feature you are proposing to solve the problem?

Add serialize() and deserialize() methods to DatabaseSync:

const { DatabaseSync } = require('node:sqlite');

// serialize: returns the database as a Uint8Array
const db = new DatabaseSync(':memory:');
db.exec("CREATE TABLE t(x TEXT)");
db.exec("INSERT INTO t VALUES ('hello')");
const buffer = db.serialize(); // Uint8Array

// deserialize: loads a buffer into the connection, replacing the current database
const db2 = new DatabaseSync(':memory:');
db2.deserialize(buffer);
db2.prepare('SELECT * FROM t').get(); // { x: 'hello' }

What alternatives have you considered?

1. VACUUM INTO + fs.readFileSync: Requires disk I/O, a temp file path, and manual cleanup
2. backup() API

[thisalihassan]

I would like to work on this. sqlite3_serialize / sqlite3_deserialize are already compiled in so this is a matter of binding them.

cc: @Renegade334 @geeksilva97 @ronag

[geeksilva97]

Go for it