feat: initialize Discord clone application with core backend services and Electron frontend.

Backend/routes/auth.js

@@ -147,7 +147,7 @@ router.post('/login/verify', async (req, res) => {
 
 router.get('/users/public-keys', async (req, res) => {
     try {
-        const result = await db.query('SELECT id, public_identity_key FROM users');
+        const result = await db.query('SELECT id, username, public_identity_key FROM users');
         res.json(result.rows);
     } catch (err) {
         console.error(err);

Backend/routes/channels.js

@@ -4,7 +4,7 @@ const db = require('../db');
 
 router.get('/', async (req, res) => {
     try {
-        const result = await db.query('SELECT * FROM channels ORDER BY name ASC');
+        const result = await db.query("SELECT * FROM channels WHERE type != 'dm' ORDER BY name ASC");
         res.json(result.rows);
     } catch (err) {
         console.error(err);

Backend/routes/dms.js

@@ -0,0 +1,79 @@
+const express = require('express');
+const router = express.Router();
+const db = require('../db');
+
+// POST /api/dms/open — Find-or-create a DM channel between two users
+router.post('/open', async (req, res) => {
+    const { userId, targetUserId } = req.body;
+
+    if (!userId || !targetUserId) {
+        return res.status(400).json({ error: 'userId and targetUserId required' });
+    }
+
+    if (userId === targetUserId) {
+        return res.status(400).json({ error: 'Cannot DM yourself' });
+    }
+
+    // Deterministic channel name so the same pair always maps to one channel
+    const sorted = [userId, targetUserId].sort();
+    const dmName = `dm-${sorted[0]}-${sorted[1]}`;
+
+    try {
+        // Check if DM channel already exists
+        const existing = await db.query(
+            'SELECT id FROM channels WHERE name = $1 AND type = $2',
+            [dmName, 'dm']
+        );
+
+        if (existing.rows.length > 0) {
+            return res.json({ channelId: existing.rows[0].id, created: false });
+        }
+
+        // Create the DM channel + participants in a transaction
+        await db.query('BEGIN');
+
+        const channelResult = await db.query(
+            'INSERT INTO channels (name, type) VALUES ($1, $2) RETURNING id',
+            [dmName, 'dm']
+        );
+        const channelId = channelResult.rows[0].id;
+
+        await db.query(
+            'INSERT INTO dm_participants (channel_id, user_id) VALUES ($1, $2), ($1, $3)',
+            [channelId, userId, targetUserId]
+        );
+
+        await db.query('COMMIT');
+
+        res.json({ channelId, created: true });
+    } catch (err) {
+        await db.query('ROLLBACK');
+        console.error('Error opening DM:', err);
+        res.status(500).json({ error: 'Server error' });
+    }
+});
+
+// GET /api/dms/user/:userId — List all DM channels for a user with the other user's info
+router.get('/user/:userId', async (req, res) => {
+    const { userId } = req.params;
+
+    try {
+        const result = await db.query(`
+            SELECT c.id AS channel_id, c.name AS channel_name, c.created_at,
+                   other_user.id AS other_user_id, other_user.username AS other_username
+            FROM dm_participants my
+            JOIN channels c ON c.id = my.channel_id AND c.type = 'dm'
+            JOIN dm_participants other ON other.channel_id = my.channel_id AND other.user_id != $1
+            JOIN users other_user ON other_user.id = other.user_id
+            WHERE my.user_id = $1
+            ORDER BY c.created_at DESC
+        `, [userId]);
+
+        res.json(result.rows);
+    } catch (err) {
+        console.error('Error fetching DM channels:', err);
+        res.status(500).json({ error: 'Server error' });
+    }
+});
+
+module.exports = router;