…s hex representation)

…ules, plus a few fixes to genuinely ambiguous tests

* "npm test" tests all three adapters

* optimize $match when it is the first step in aggregation, don't fetch the whole collection 😜
* multipostgres listDatabases() and .db() should return and expect "fully qualified virtual database names," e.g. physical_db_name-schemaname

… in tests

documentation improvements

…w on unrecognized operators. It should, and it should support the same mongodb operators that the regular find()

  path does in postgres/sqlite (our official subset), unless there is an extraordinary reason not to.

  * Similarly, the main query implementation for normal queries should throw on unrecognized operators if it doesn't already.

  * The dump/restore programmatic APIs in db-connect concern me. These involve returning the entire database as a string, which could exhaust memory. This impacts both utilities and
  also copyDatabase(). Could these APIs return and expect async iterators instead of strings?

  * The test "anchored regex on an indexed field uses a btree index search" runs explain on a query that's hardcoded in the test. Instead these SQL based adapters should expose a means
  to get the SQL for a query, so it can be directly tested. Otherwise this test proves nothing as changes to the adapter accumulate in future.

  * Why is this test searching for "at least 1" and not exactly 1?

  it('should find documents with null value', async function() {
    const docs = await db.collection('test').find({ value: null }).toArray();
    // MongoDB matches both null and missing fields with { value: null }
    expect(docs.length).to.be.at.least(1);
  });

  * What is the maximum size of a db-connect document in the postgres and sqlite adapters?

  * Update the copyright year in db-connect/LICENSE.md to 2025.

  * The db-connect README mentions: sqlite://:memory: What happens if you try to use .db('some-name') with that? I think it would be best to just not support throwaway in-memory sqlite
  databases because I doubt anyone would intentionally store a website in one.