Queue: inject a logger into Worker instead of calling error_log() #608

Problem

Marko\Queue\Worker reports stop reasons, timeouts and failures with error_log(). Since #551 (PR #602) added a shared "Worker stopping" line, about 100 worker tests print that line to the test output under PHPUnit 12, which captures error_log() per test. The tests still pass, but the noise hides real output. Apps also can't send worker logs anywhere other than PHP's error log.

Proposal

Inject Marko's LoggerInterface (marko/log) into Worker and the alarm-handler path, and log through it. marko/log binds LoggerInterface itself since #555, so no extra driver choice is needed. Tests pass a FakeLogger (from marko/testing) and assert on the stop line rather than printing it. If marko/queue shouldn't hard-require marko/log, define a tiny queue-owned logging contract instead and say why in the PR.

Exit criteria

• No error_log() calls left in packages/queue/src
• The worker test suite prints nothing extra; stop lines are asserted through FakeLogger
• Docs: queue page says where worker logs go
• composer ci green

Follow-up from #551.