Security improvements, role in user creation, todo filters fix

- Remove better-auth dependency (unused)
- Update JWT secrets to stronger values
- Add ENCRYPTION_SALT env variable for password encryption
- Add role field to createUserSchema validator
- Accept role from body in admin.controller createUser
- Fix todo filters: add priority filter, handle completed param
- Remove .env.example (merged into .env)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/controllers/todo.controller.js

@@ -7,14 +7,21 @@ import { formatErrorResponse } from '../utils/errors.js';
  */
 export const getAllTodos = async (req, res) => {
   try {
-    const { search, projectId, companyId, assignedTo, status } = req.query;
+    const { search, projectId, companyId, assignedTo, status, completed, priority } = req.query;
+
+    // Handle both 'status' and 'completed' query params
+    let statusFilter = status;
+    if (completed !== undefined) {
+      statusFilter = completed === 'true' ? 'completed' : 'pending';
+    }
 
     const filters = {
       searchTerm: search,
       projectId,
       companyId,
       assignedTo,
-      status,
+      status: statusFilter,
+      priority,
     };
 
     const todos = await todoService.getAllTodos(filters);