feat: Support syntax helper for "bulk insert with parameters"

A pattern that is a bit of a pain for us is doing an INSERT with multiple rows at once.

While we support explicitly doing something like:

execute("INSERT INTO x VALUES (?, ?, ?), (?, ?, ?)", [1, 2, 3, 4, 5, 6])

It puts the burden on the user to create all of the (?, ?, ?) placeholders.

An API similar to:

bulkinsert("INSERT INTO x VALUES", [[1, 2, 3], [4, 5, 6]])

would help utilize this without the client needing to construct all of the placeholders.

We could even just provide this as a separate function that's passed into execute() as just a "query builder" thing.

So something like:

execute(createBulkInsert("INSERT INTO x VALUES", [[1, 2, 3], [4, 5, 6]]))

And createBulkInsert would return the SQL.

It's just all around a bit awkward to need to have one big flat list of all the parameters vs passing in more logical "rows".

Start by tracing the existing execute API and its parameter handling, which the issue uses in its examples. Compare the proposed bulkinsert and createBulkInsert shapes, then define how rows become placeholders and bound parameters. Done means a supported bulk-insert helper with documented behavior and coverage for the multi-row example; the issue does not name specific files or tests.