6.x extend: fixes and additions from porting craftcms/guest-entries

[lukeholder]

Summary

Corrections and additions to the Craft 6.x extension docs, found by porting craftcms/guest-entries (Craft 5 to a native, adapter-free Craft 6 plugin) on craftcms/cms 6.0.0-alpha.20. Every change was checked against the installed source or by running the code.

The ported plugin is on the 5.x-via-skill branch of craftcms/guest-entries.

Changes

• extend/provider.md
  • createSettings() is documented without its signature. It is protected static function createSettings(): ?PluginSettings; a copy of the old non-static createSettingsModel() signature is a fatal error.
  • Adds a warning that after switching to CraftCms\Cms\Plugin\Plugin, the adapter no longer routes actions/{handle}/… to the plugin (it only routes to Yii plugins). Yii controllers return a 404 until they are ported and routed in routes/actions.php, and settingsHtml() is replaced by settingsForm(). The current text says the plugin is "in a stable state" after the switch, which isn't true for plugins with controllers.
• extend/session.md, extend/http.md: Auth::craftUser() does not exist (it throws SessionGuard::craftUser does not exist). Documents $request->craftUser() and the currentUser() / currentUserElement() helpers.
• extend/http.md: new CSRF section: Laravel returns 419 without a token, and PreventRequestForgery::except() is the equivalent of disabling enableCsrfValidation on a Yii controller (Craft uses it for graphql/api).
• extend/upgrade.md: PluginSettings extends Component, which has no attributes(), so a settings class that moves to it can't call parent::attributes().
• extend/structure.md: new "Class Organization" section recommending a PascalCase namespace and Craft's own layout (Http/Controllers, Events, Data, Models, ...), with core examples.
• Fixes broken links (approach.md, commands.md, config.md) and an unfinished comment in local-dev.md.

Not changed (needs a maintainer's call)

• provider.md says not to add extra.laravel.providers; structure.md shows it as an option.
• The mailer config file is config/mail.php in approach.md and config/mailer.php in mail.md.
• The auth methods registry is AuthMethodCatalog in avenues.md and AuthMethods in registries.md.
• extend/elements.md is an empty page.
• Separately, a Craft bug (not docs): when plugin settings validation fails, PluginsController::saveSettings() throws a TypeError because it returns a CpScreenResponse where Response is declared.

🤖 Generated with Claude Code

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