[clue]

This changeset updates the test suite to ensure 100% code coverage.

The coverage check skips legacy PHP 5.3, as createReceiver() requires PHP 5.4+ and can not be covered there. This also removes the explicit SO_REUSEADDR socket option, as PHP already sets this for all stream sockets, so multiple receivers can still share the same port.

Builds on top of #28, #27 and clue/reactphp-eventsource#35
Refs reactphp/socket#236

[Copilot]

🟡 Changes recommended

The coverage gate can succeed without a valid coverage report, undermining its enforcement.

1 open issue

• Reject missing or invalid coverage reports · New

What changed in this PR

This PR expands test coverage for the multicast socket factory and adds a CI gate intended to enforce 100% coverage, excluding legacy PHP 5.3.

Changes:

• Add tests for socket creation failures and use a dynamically selected port in the invalid-address test.
• Remove redundant SO_REUSEADDR configuration and adjust coverage exclusions.
• Generate and check Clover coverage reports, with a README badge and local reporting instructions.

File	Description
tests/​FunctionalTest.php	Add failure-path tests and replace a fixed test port.
src/​Factory.php	Simplify socket setup and annotate unsupported-environment branches.
README.md	Document coverage expectations and report generation.
.github/​workflows/​ci.yml	Generate Clover reports and enforce full coverage on PHP 5.4+.

_{Review effort: Balanced}