fix: avatar upload 500 — increase PHP upload limits + better errors

Add upload_max_filesize=10M to PHP config (default 2M was rejecting
compressed images). Add fileinfo extension explicitly. Improve error
messages in avatar.php to report the actual failure reason.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

 FROM php:8.3-apache
 
 RUN apt-get update && apt-get install -y libpq-dev libcurl4-openssl-dev \
-    && docker-php-ext-install pdo pdo_pgsql pgsql curl \
+    && docker-php-ext-install pdo pdo_pgsql pgsql curl fileinfo \
     && apt-get clean && rm -rf /var/lib/apt/lists/*
 
+RUN echo "upload_max_filesize = 10M\npost_max_size = 12M\nmax_file_uploads = 5" > /usr/local/etc/php/conf.d/uploads.ini
+
 RUN a2enmod rewrite headers
 
 ENV APACHE_DOCUMENT_ROOT=/var/www/html

api/avatar.php

@@ -15,8 +15,12 @@ $token = requireAuth();
 $userId = getUserId($token);
 if (!$userId) jsonError('Invalid user', 401);
 
-if (!isset($_FILES['avatar']) || $_FILES['avatar']['error'] !== UPLOAD_ERR_OK) {
-    jsonError('No file uploaded');
+if (!isset($_FILES['avatar'])) {
+    jsonError('No file in request. Check upload_max_filesize (' . ini_get('upload_max_filesize') . ')');
+}
+if ($_FILES['avatar']['error'] !== UPLOAD_ERR_OK) {
+    $errors = [1 => 'File exceeds server limit', 2 => 'File exceeds form limit', 3 => 'Partial upload', 4 => 'No file sent', 6 => 'No tmp dir', 7 => 'Write failed'];
+    jsonError($errors[$_FILES['avatar']['error']] ?? 'Upload error ' . $_FILES['avatar']['error']);
 }
 
 $file = $_FILES['avatar'];