fix: POST /v1/dateien stichwoerter variable scoping bug (#245)

[Avatarsia]

Summary

• Fix variable scoping bug in FileController::createAction() where $stichwoerter was only initialized inside the if-block but used in the foreach outside it
• Add isset() check to prevent PHP Notice on missing array key

Problem

When uploading files via POST /v1/dateien with stichwoerter parameters for object binding (e.g. attaching a file to an Auftrag), the stichwoerter are silently ignored. The file is created but without any object association. Files created through the PHP UI work correctly.

Root Cause

$stichwoerter = array() was defined on line 128 inside the if (is_array(...)) block, but the foreach ($stichwoerter as ...) on line 176 runs outside that block. When the if condition is false, $stichwoerter is undefined. The resulting PHP Warning is masked by error_reporting(E_ERROR) in www/api/index.php.

Fix (2 lines changed)

-        if (is_array($input['stichwoerter'])) {
-            $stichwoerter = array();
+        $stichwoerter = array();
+        if (isset($input['stichwoerter']) && is_array($input['stichwoerter'])) {

Test plan

• Upload file via API with stichwoerter — verify datei_stichwoerter table entry created
• Upload file via API without stichwoerter — verify no error, file created normally
• Upload file via UI — verify unchanged behavior

Fixes #245