add detach files feature, utf8 filename fix, and error pages

db/init.sql

@@ -59,9 +59,10 @@ CREATE INDEX IF NOT EXISTS idx_group_photos_group_id ON group_photos(group_id);
 
 CREATE TABLE IF NOT EXISTS project_files (
   id SERIAL PRIMARY KEY,
-  entry_id INT NOT NULL REFERENCES entries(id) ON DELETE CASCADE,
+  entry_id INT REFERENCES entries(id) ON DELETE CASCADE,
   token VARCHAR(64) UNIQUE NOT NULL,
   path VARCHAR(255) NOT NULL,
   name VARCHAR(255) NOT NULL,
-  created_at TIMESTAMPTZ DEFAULT now()
+  created_at TIMESTAMPTZ DEFAULT now(),
+  detached_at TIMESTAMPTZ
 );