[MaolmeoX]

ParameterizedSQL.join builds the joined SQL and a single fresh params array in one pass, instead of calling ParameterizedSQL.append once per statement, which copied the accumulated params array every time. Every inq / nin clause goes through join with one statement per value, so the cost was quadratic in the number of values.

Measured on Node 24.19 with the script from the issue:

Statements joined	Before	After
20,000	483 ms	1 ms
35,000	2,366 ms	2 ms
50,000	5,115 ms	18 ms

buildWhere with an inq of 35,000 ids goes from 2,318 ms to 24 ms.

The output is unchanged: same separator handling (including statements with an empty sql), same params order, and plain strings and {sql, params} objects are still normalized through the constructor. 20,000 random joins compared old against new produced identical results. The params arrays of the joined statements are not modified: the constructor keeps the caller's array by reference, so the result gets its own array.

Tests added in test/sql.test.js: the joined result for mixed input, the joined statements' params left untouched, and a join of 50,000 statements under a 1 s mocha timeout. That last test takes about 5 s and fails on the current code, and about 20 ms with this change.

Fixes #1003

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