Feat/use forecasting endpoint hems

[BelhsanHmida]

Description

This PR updates the HEMS script to trigger forecasts using the forecasting endpoint /sensors/{id}/forecasts/trigger instead of running forecasts through the CLI.

How to test

1. Run the HEMS script with the updated implementation.
2. Verify that forecasts are successfully triggered via the /sensors/{id}/forecasts/trigger endpoint.
3. Compare the generated forecasts with those obtained when running the forecasts using the CLI.
4. Confirm that the overall HEMS results remain the same as before.

The forecasts and final HEMS outputs should match the results produced when using the CLI-based workflow.

closes #160

[nhoening]

@BelhsanHmida please pick this up again.

And one thought: we should check if we run the HEMS example against a FM server of at least v0.31, and otherwise raise an error message.

[BelhsanHmida]

@BelhsanHmida please pick this up again.

And one thought: we should check if we run the HEMS example against a FM server of at least v0.31, and otherwise raise an error message.

Added that check. The HEMS example now verifies the connected FlexMeasures server is at least v0.31.0 before doing any setup work, and it raises a clear InsufficientServerVersionError with a HEMS-specific message if the server is too old. I also factored the logic into a reusable ensure_minimum_server_version(...) helper on the client and added tests for it.

[BelhsanHmida]

This PR now produces the same results as the CLI-based flow, so the forecasting API integration in the HEMS script is ready. We can now run it using the forecasting queue. Also, running multiple forecasting workers will speed up the forecasting part.

Results:

[nhoening]

Nice!

I have three minor improvements.

[nhoening]

Good iteration, but I got the feeling you have not tested the error handling for forecasting jobs.

[Copilot]

Pull request overview

This PR updates the HEMS tutorial workflow to use the FlexMeasures forecasting API endpoint (/sensors/{id}/forecasts/trigger) instead of relying on the FlexMeasures CLI, and adds supporting client logic/tests to improve version gating and error surfacing.

Changes:

• Add ensure_minimum_server_version helper to the client and use it in the HEMS setup script.
• Update HEMS forecasting example to trigger forecasts via the API and poll until completion.
• Improve API error surfacing for responses containing a message, with accompanying tests.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/flexmeasures_client/client.py	Adds ensure_minimum_server_version and refactors request-version checking to reuse it.
src/flexmeasures_client/response_handling.py	Surfaces API message fields as ValueErrors for non-2xx responses.
examples/HEMS/forecasting.py	Replaces CLI-based forecasting with trigger_forecast + get_forecast polling.
examples/HEMS/HEMS_setup.py	Enforces minimum server version required by the HEMS example.
docs/HEMS.rst	Updates tutorial documentation to reflect API-based forecasting and worker queue setup.
tests/client/test_init.py	Adds tests for ensure_minimum_server_version.
tests/client/test_forecast.py	Adds coverage for forecast job failure responses including API message.

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[nhoening]

Thanks!