[shelly] Add support for Shelly Plug M Gen3

[kaenguruhs]

Importance

provides a new addon / adds a new thing

Description

This PR adds support for the Shelly Plug M Gen3.
The device is identified by the model ID S3PL-30110EU.

Technical changes:

• Added SHELLYDT_PLUSPLUGM_G3 and mapping to ShellyDevices.java.
• Updated ShellyThingCreator.java to correctly handle Gen3 discovery for this model.
• Updated shellyGen2_relay.xml description to include the "M" variant.
• Updated README.md to include "M" variant.

Testing

• Tested with a physical Shelly Plug M Gen3 device.
• Manual discovery works.
• Power metering and switching work as expected.
• JAR for manual testing (rename to *.jar): org.openhab.binding.shelly-5.2.0-SNAPSHOT.zip

Legal Process

• I have signed my commits (DCO).

Closes #20631.

[kaenguruhs]

Updated the PR with missing UI definitions and adjusted the unit tests. New *.jar is here: org.openhab.binding.shelly-5.2.0-SNAPSHOT.zip

[Copilot]

Pull request overview

Adds Shelly binding support for the Shelly Plug M Gen3 (model id S3PL-30110EU) by mapping it into the existing Gen2/Gen3 RPC “Plus Plug” thing type and ensuring discovery/identification recognizes the new service/model identifiers.

Changes:

• Add the new model id constant and map S3PL-30110EU to a supported thing type.
• Adjust discovery/type resolution to avoid misclassifying shellyplugmg3-* as a Gen1 “shellyplug”.
• Update tests and user-facing descriptions/docs to include the “M” variant.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
bundles/org.openhab.binding.shelly/src/main/java/org/openhab/binding/shelly/internal/ShellyDevices.java	Adds model id mapping for Plug M Gen3 and service-name mapping for shellyplugmg3.
bundles/org.openhab.binding.shelly/src/main/java/org/openhab/binding/shelly/internal/discovery/ShellyThingCreator.java	Ensures shellyplugmg3-* doesn’t get routed through the Gen1 plug name mapping.
bundles/org.openhab.binding.shelly/src/test/java/org/openhab/binding/shelly/internal/discovery/ShellyThingCreatorTest.java	Extends service-name and device-type mapping test cases for Plug M Gen3.
bundles/org.openhab.binding.shelly/src/test/java/org/openhab/binding/shelly/internal/api/ShellyDeviceProfileTest.java	Adds Plug M thing type to the generation/API determination test matrix.
bundles/org.openhab.binding.shelly/src/main/resources/OH-INF/thing/shellyGen2_relay.xml	Updates the shellyplusplug thing type description to include “M”.
bundles/org.openhab.binding.shelly/src/main/resources/OH-INF/i18n/shelly.properties	Updates the English i18n description for shellyplusplug.
bundles/org.openhab.binding.shelly/src/main/resources/OH-INF/i18n/shelly_de.properties	Updates the German i18n description for shellyplusplug.
bundles/org.openhab.binding.shelly/README.md	Adds the Plug M Gen3 model id to the supported device table.

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[lsiepel]

See copilot comments

[lsiepel]

Thanks LGTM

Waiting for @markus7017 to confirm

[markus7017]

@kaenguruhs Looks good, could you please add the new device type to the unit tests (ShellyDeviceProfileTest, ShellyThingCreatorTest)

[kaenguruhs]

Hi @markus7017,

in ShellyThingCreatorTest.java I added the new plug:

• https://github.com/openhab/openhab-addons/pull/20632/changes#diff-1cfe827ac2e22ad6f1483fc22a11f277f86d270acc0339eecbfabf22d2ab527aR82
• https://github.com/openhab/openhab-addons/pull/20632/changes#diff-1cfe827ac2e22ad6f1483fc22a11f277f86d270acc0339eecbfabf22d2ab527aR193

In ShellyDeviceProfileTest I did not add the new plug M as I did not add a new THING_TYPE (just like the PLUSPLUGIT, which is not mentioned in there, too).

What do you expect me to do?

[markus7017]

LGTM

[lsiepel]

One final comment. Otherwise LGTM