feat: add rate limited publisher

[wakonig]

This PR adds rate limiting to ophyd callbacks: A shared pipeline publisher is introduced to coalesce messages during a cooldown window and ensures that the latest message is emitted afterwards. On local tests, this was running with around 300 k msgs / s.

A warning is issued if the update rate per topic is higher than 200 Hz. This should give us better debugging feedback next time we encounter "funny" ECMC problems

[codecov]

Codecov Report

❌ Patch coverage is 93.16770% with 11 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
..._server/devices/rate_limited_pipeline_publisher.py	94.03%	5 Missing and 4 partials ⚠️
.../bec_server/device_server/devices/devicemanager.py	80.00%	2 Missing ⚠️

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[Copilot]

Pull request overview

This PR introduces a shared, rate-limited Redis pipeline publisher for device-server ophyd callbacks to coalesce high-frequency updates per topic and optionally raise a warning when input update rates exceed a threshold.

Changes:

• Added RateLimitedPipelinePublisher background worker that batches Redis set / set_and_publish operations and coalesces per-topic updates during a cooldown window.
• Updated DeviceManagerDS ophyd callbacks (limits/readback/config/status/progress) to publish via the rate-limited publisher and added shutdown wiring.
• Added unit tests for the new publisher and adjusted existing device-manager tests to account for the new publish path.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
bec_server/bec_server/device_server/devices/rate_limited_pipeline_publisher.py	New coalescing publisher with background flush thread and optional high-update-rate warning alarm.
bec_server/bec_server/device_server/devices/devicemanager.py	Routes several ophyd callbacks through the new rate-limited publisher and shuts it down on manager shutdown.
bec_server/tests/tests_device_server/test_rate_limited_pipeline_publisher.py	New tests covering coalescing behavior, per-topic isolation, shutdown flush, and warning alarm.
bec_server/tests/tests_device_server/test_device_manager_ds.py	Updates progress callback test to mock the new publish mechanism; reorders file-event test block.

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