chore: IConfig -> IAppConfig/IUserConfig (deprecation)

[rubenvdlinde]

Summary

This is the pilot PR that defines the fleet migration pattern for deprecated OCP\IConfig app/user-value calls.

App-value calls (0 migrated)

No getAppValue/setAppValue calls exist. ActionAuthService and SettingsService already use the modern IAppConfig::getValueString/setValueString API — no migration needed.

User-value calls (3 intentionally LEFT)

PreferencesController.php lines 80/123/129 use IConfig::getUserValue, setUserValue, deleteUserValue.

Reason left: appinfo/info.xml declares <nextcloud min-version="28"/>. OCP\IUserConfig requires Nextcloud ≥ 31. These three calls must stay on IConfig until min-version is bumped to 31. A TODO comment pointing to this is the recommended fleet pattern.

Migration target API (for when min-version reaches 31):

use OCP\IUserConfig;
// inject: private readonly IUserConfig $userConfig

// get
$value = $this->userConfig->getValueString($uid, Application::APP_ID, 'pref_'.$safeKey, '');
// set
$this->userConfig->setValueString($uid, Application::APP_ID, 'pref_'.$safeKey, $value);
// delete
$this->userConfig->deleteUserValue($uid, Application::APP_ID, 'pref_'.$safeKey);

Pre-existing PHPCS/PHPStan errors fixed

Touched files had pre-existing quality gate failures — fixed per project policy:

• HealthController / MetricsController: missing named params on parent::__construct
• ActionAuthService: missing named params on internal method calls; redundant always-false type guards in setMatrix removed (PHPStan level-5); blank-line-after-function
• InitializeActions: concat operator spacing; inline ternary → if/else; blank-line-after-function

Quality results

Tool	Result
php -l	No syntax errors (all edited files)
PHPStan	✅ No errors
PHPCS (errors)	✅ No errors (warnings are @spec tag placeholders across scaffold classes — tracked separately)
Deprecated call re-grep	✅ 0 app-value calls; 3 user-value calls intentionally left (min-version<31)

Fleet pattern

When fanning this out to other apps:

1. Grep for getAppValue/setAppValue → replace with IAppConfig::getValueString/Int/Bool/Array (inject OCP\IAppConfig $appConfig)
2. Grep for getUserValue/setUserValue/deleteUserValue → check min-version first; if ≥ 31 replace with IUserConfig::getValueString/setValueString/deleteUserValue (inject OCP\IUserConfig $userConfig); if < 31 leave with a TODO comment
3. Remove use OCP\IConfig only when no system-value calls remain