Add admin login and password change endpoints

Introduces POST /login and PATCH /password routes for admin authentication and password management. Adds corresponding schema validation for login and password change, enforces stricter password requirements, and updates adminService with JWT-based profile retrieval and improved token handling.

routes/admin/index.js

@@ -1,4 +1,21 @@
 const express = require("express")
-const router = express.Router() 
+const router = express.Router()
+const adminService = require("../../services/adminService")
+
+router.post("/login", async (req, res) => {
+    const { username, password } = req.body
+    const result = await adminService.loginAdmin(username, password)
+    return res.status(200).json(result)
+})
+
+router.patch("/password", async (req, res) => {
+    const token = req.headers.authorization.replace("Bearer ", "")
+    const profile = await adminService.getAdminProfileByToken(token)
+
+    const { newPassword } = req.body
+
+    const result = await adminService.changeAdminPassword(profile.id, newPassword)
+    return res.status(200).json(result)
+})
 
 module.exports = router