fix: serialize query params with the documented encoding

[javorosas]

What

BaseClient::arrayToParams() now emits the query encoding the API documents and the other official SDKs send:

• Lists repeat the key: status=valid&status=canceled (was status[0]=valid&status[1]=canceled).
• null values are omitted instead of being sent empty (q=). Passing an empty string still sends an explicit empty value (q=).
• Associative arrays keep bracket notation (date[gte]=...&date[lte]=...) and booleans keep true/false.

This aligns the encoding with the deepObject style documented for nested filters and the default form + explode style for arrays, and with the other SDKs, so the same search sends the same URL everywhere.

Tests

vendor/bin/phpunit
OK (55 tests, 201 assertions)

New cases cover a list value, a null value, and an explicit empty string.

Release note

VERSION.md records the fix under the pending 4.8.0 entry.

[Copilot]

🟢 Approval recommended

The functional changes are well-covered by tests and align with the stated API encoding, with only a minor release-note spelling nit identified.

Pull request overview

Updates BaseClient::arrayToParams() to serialize query parameters using the encoding documented by the API (and used by other official SDKs), ensuring consistent URLs for equivalent searches across SDKs.

Changes:

• Refactors query parameter serialization to repeat keys for list values, keep bracket notation for associative arrays, and omit null values.
• Adds PHPUnit coverage for list repetition, null omission, and explicit empty-string handling.
• Records the fix under the pending 4.8.0 entry in VERSION.md.

File summaries

File	Description
src/Http/BaseClient.php	Implements the updated query parameter encoding via a dedicated helper.
tests/Resources/InvoicesTest.php	Adds regression tests for list, null, and empty-string query parameter behavior.
VERSION.md	Documents the serialization change in the pending release notes.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Lite

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