Initial commit: Next.js UWB positioning webapp

- Complete Next.js 14 app with TypeScript and Tailwind CSS
- ESP32 serial communication via API routes
- Real-time UWB positioning visualization
- Interactive 2D warehouse mapping with Canvas
- Device connection interface with auto-detection
- AT command parsing for UWBHelper library integration
- Clean project structure with comprehensive documentation

pages/api/serial/connect.ts

@@ -0,0 +1,91 @@
+import { NextApiRequest, NextApiResponse } from 'next'
+import { SerialPort } from 'serialport'
+import { ReadlineParser } from '@serialport/parser-readline'
+
+// Global connection state
+let serialConnection: SerialPort | null = null
+let parser: ReadlineParser | null = null
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  if (req.method === 'POST') {
+    const { port, baudRate = 115200 } = req.body
+
+    if (!port) {
+      return res.status(400).json({ message: 'Port is required' })
+    }
+
+    try {
+      // Close existing connection
+      if (serialConnection?.isOpen) {
+        serialConnection.close()
+      }
+
+      // Create new connection
+      serialConnection = new SerialPort({
+        path: port,
+        baudRate: baudRate,
+        autoOpen: false
+      })
+
+      // Set up parser for line-based data
+      parser = serialConnection.pipe(new ReadlineParser({ delimiter: '\r\n' }))
+
+      // Open connection
+      await new Promise<void>((resolve, reject) => {
+        serialConnection!.open((err) => {
+          if (err) reject(err)
+          else resolve()
+        })
+      })
+
+      res.status(200).json({
+        message: 'Connected successfully',
+        port,
+        baudRate,
+        isOpen: serialConnection.isOpen
+      })
+
+    } catch (error) {
+      console.error('Serial connection error:', error)
+      res.status(500).json({
+        message: 'Failed to connect',
+        error: error instanceof Error ? error.message : 'Unknown error'
+      })
+    }
+  }
+  
+  else if (req.method === 'DELETE') {
+    // Disconnect
+    try {
+      if (serialConnection?.isOpen) {
+        serialConnection.close()
+        serialConnection = null
+        parser = null
+      }
+      
+      res.status(200).json({ message: 'Disconnected successfully' })
+    } catch (error) {
+      res.status(500).json({ 
+        message: 'Failed to disconnect',
+        error: error instanceof Error ? error.message : 'Unknown error'
+      })
+    }
+  }
+  
+  else if (req.method === 'GET') {
+    // Get connection status
+    res.status(200).json({
+      connected: serialConnection?.isOpen || false,
+      port: serialConnection?.path || null
+    })
+  }
+  
+  else {
+    res.status(405).json({ message: 'Method not allowed' })
+  }
+}
+
+export { serialConnection, parser }