feat: Add Custom Help URL Support for Extension Actions/Conditions/Expressions

[malec-palec]

Summary

Adds the ability for extension authors to specify a custom help URL for their actions, conditions, and expressions. When a URL is provided, a help icon (question mark) appears next to the instruction description in the parameter editor dialog, allowing users to quickly access external documentation.

Changes

Core (C++)

• Added helpUrl field to EventsFunction with getter/setter methods
• Updated serialization to persist helpUrl in project files

GDevelop.js Bindings

• Exposed getHelpUrl() and setHelpUrl() methods to JavaScript
• Updated type declarations

Metadata Generation

• Updated MetadataDeclarationHelper to propagate helpUrl to InstructionMetadata and ExpressionMetadata

Editor UI

• Added "Help page URL" input field with URL validation in the extension function properties editor
• Added help icon next to the instruction description in the parameter editor dialog when a custom URL is set
• Preserved existing "Help for this action/condition" button for wiki-based help paths

Utils

• Added isDocumentationAbsoluteUrl() and isRelativePathToDocumentationRoot() helpers to distinguish between custom URLs and wiki paths
• Updated getHelpLink() to pass through absolute URLs as-is

Tests

• C++ unit tests for EventsFunction helpUrl get/set and serialization
• GDevelop.js binding tests for EventsFunction and MetadataDeclarationHelper helpUrl propagation
• React tests for HelpLink utility functions
• Updated Storybook for HelpIcon component

Screenshots

[4ian]

Finally back to this! Thanks for your patience.

This seems very heavy to have (?) on every row in the selector of actions/conditions or expressions:

Imagine if we add a customized help url for each action, the list will be full of (?). There is a high chance this discourage power users (GDevelop is often said to be visually "too heavy") and there is the phenomena of "content blindness" (if you have too many (?), users start to ignore them).

=> I would remove these in the list and would only keep it in the plain dialogs. What do you think? If that's ok let's remove it and then we can merge this. I did some minor improvements regarding layouting.

[4ian]

Thanks for the updates 👍