Add guideline for defining the name of a controller

[mcmire]

Explanation

There is no written standard for defining the name of a controller, and some contributors do not have a common understanding of the do's and dont's for the name.

This commit adds such a guideline, highlighting the following points:

• The name of a controller should be defined in a variable called CONTROLLER_NAME (formerly controllerName)
• The name should be used to define custom actions and events and should be passed to BaseController
• The name should not be exported from the package

Besides updating the guidelines, this commit also updates the sample-controllers package to follow them, most notably changing controllerName to CONTROLLER_NAME and removing the export from this constant.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Medium Risk
Removes an exported constant and renames controllerName to CONTROLLER_NAME in sample controllers, which could break any consumers importing that symbol even though runtime behavior is unchanged.

Overview
Adds a new controller guideline requiring a single internal CONTROLLER_NAME constant to namespace messenger actions/events and BaseController state, and explicitly discouraging exporting that constant from the package.

Updates the sample-controllers examples (sample-gas-prices-controller and sample-petnames-controller) to follow the guideline by replacing exported controllerName with an internal CONTROLLER_NAME and wiring all messenger/type and BaseController references to it.

^{Reviewed by Cursor Bugbot for commit 4757fdb. Bugbot is set up for automated code reviews on this repo. Configure here.}

[mcmire]

Adding no-changelog because this is a non-public-facing change to sample-controllers.

[Mrtenz]

Probably not necessary to include this.

Suggested change

	The name should be defined in a constant called `CONTROLLER_NAME` so that it can be easily changed if the need arises. (This variable was formerly called `controllerName`.) The name should be used to initialize the messenger, and should also be passed to the `BaseController` constructor.
	The name should be defined in a constant called `CONTROLLER_NAME` so that it can be easily changed if the need arises. The name should be used to initialize the messenger, and should also be passed to the `BaseController` constructor.

[mcmire]

Updated in b450e6d.

[Mrtenz]

This example doesn't really make sense given the MESSENGER_EXPOSED_METHODS pattern. Maybe update it to use ControllerGetStateAction or some events?

[mcmire]

Yeah, you're right. In fact most of the examples in this document don't make much sense anymore 😅 I will update this.

[mcmire]

Okay, I've updated these examples here: b450e6d. I replaced FooController with a more realistic name and I used events instead of actions for the examples.