Add queue depth telemetry gauge

[ChiragAgg5k]

Summary

• Adds a messaging.queue.depth gauge initialized with the queue server telemetry.
• Records pending queue size on worker start and after each processed message when the consumer also implements Publisher::getQueueSize().
• Covers the supported and unsupported consumer paths with an in-process server telemetry test.

Type of Change

• New feature

Testing

• vendor/bin/phpunit tests/Queue/E2E/Adapter/ServerTelemetryTest.php
• vendor/bin/phpstan analyse src/Queue/Server.php tests/Queue/E2E/Adapter/ServerTelemetryTest.php --memory-limit=1G
• vendor/bin/pint --test src/Queue/Server.php tests/Queue/E2E/Adapter/ServerTelemetryTest.php

Full vendor/bin/phpunit was attempted locally, but the AMQP E2E tests require the amqp:5672 service hostname and failed DNS resolution outside the Docker test environment.

[greptile-apps]

Greptile Summary

This PR introduces a messaging.queue.depth gauge to the queue server's telemetry, recorded once at worker start and again after every processed message when the consumer also implements Publisher::getQueueSize(). A dedicated test file exercises the three key paths using lightweight in-process stubs so no external broker is needed.

• src/Queue/Server.php: setTelemetry() now creates the gauge; the new private recordQueueDepth() guards on instanceof Publisher, calls getQueueSize(), and records the result with messaging.destination.name / messaging.destination.namespace attributes.
• tests/Queue/E2E/Adapter/ServerTelemetryTest.php: Covers the publisher path (depth recorded), the non-publisher path (skipped), and the failure path (silently swallowed, no values recorded).

Confidence Score: 5/5

Safe to merge — the change is additive, guarded by an interface check, and does not alter any existing message-processing behavior.

The gauge is always initialized (constructor calls setTelemetry(new NoTelemetry())) so no uninitialized-property risk exists. The instanceof Publisher guard ensures nothing changes for consumers that do not support getQueueSize(). The finally-block placement means queue depth is captured after every message without interfering with the success/error callback flow. All three behavioral paths are covered by the new test.

No files require special attention.

Important Files Changed

Filename	Overview
src/Queue/Server.php	Adds messaging.queue.depth gauge, initialized in setTelemetry() and recorded on worker start and after each message's finally block via the new recordQueueDepth() helper. Logic is correct; silent Throwable catch was flagged in a previous review thread.
tests/Queue/E2E/Adapter/ServerTelemetryTest.php	New in-process test covering three paths: publisher consumer records expected depths, non-publisher consumer records nothing, and a failing publisher consumer is silently swallowed and records nothing. Test stubs are self-contained and correct.

_{Reviews (3): Last reviewed commit: "Simplify queue depth error telemetry" | Re-trigger Greptile}