Add upload security: size limit, per-user and site-wide post caps

Reject base64 payloads over 10 MB, limit users to 50 posts each,
and cap total posts at 10,000 (~650 MB on disk). Document upload
security model in README.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/app/Models/Post.php b/src/app/Models/Post.php
index 66c8c18..e82b0d9 100644
--- a/src/app/Models/Post.php
+++ b/src/app/Models/Post.php
@@ -42,6 +42,13 @@ class Post
         return $stmt->fetchAll();
     }
 
+    public function countByUserId(int $userId): int
+    {
+        $stmt = $this->pdo->prepare('SELECT COUNT(*) FROM posts WHERE user_id = :user_id');
+        $stmt->execute(['user_id' => $userId]);
+        return (int) $stmt->fetchColumn();
+    }
+
     public function findAllPaginated(int $limit, int $offset): array
     {
         $stmt = $this->pdo->prepare(