Add new $flush parameter to control flush mode for Compressor

[clue]

This changeset adds a new $flush parameter to control the flush mode for Compressor. This is particularly useful for streaming protocols like WebSocket/EventSource to make sure data can be received immediately after writing with ZLIB_SYNC_FLUSH.

Builds on top of #30 and #28

[Copilot]

Pull Request Overview

This PR adds a new $flush parameter to the Compressor class constructor to control the compression flush mode, enabling immediate data availability for streaming protocols like WebSocket and EventSource through ZLIB_SYNC_FLUSH.

• Added optional $flush parameter to Compressor constructor with validation
• Updated transformData method to use the specified flush mode instead of hardcoded ZLIB_NO_FLUSH
• Added comprehensive test coverage for different flush modes including default, sync flush, and finish flush behaviors

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/Compressor.php	Added flush parameter with validation and updated transform logic to use it
tests/CompressorTest.php	Added test for invalid flush mode validation
tests/GzipCompressorTest.php	Added extensive tests for different flush modes and their output behavior

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[Copilot]

Pull Request Overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

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