Enhance logging functionality in API and UI components

- Implemented detailed logging for USB serial communication in readdevice.js.
- Added log file management features in logfile.php, including deletion and selection of log files.
- Created a new communication log API endpoint in com_log.php to store USB communication data.
- Improved user interface for log file selection and added confirmation for log deletion.

api/v2/post/com_log.php

@@ -0,0 +1,88 @@
+<?php
+//defined($security_key) or exit;
+
+//------------------------------------------
+// Communication Log API endpoint
+// Stores all USB serial communication data in date-organized files
+//------------------------------------------
+$request = explode('/', trim($_SERVER['PATH_INFO'],'/'));
+
+//------------------------------------------
+// Application related calls
+//------------------------------------------
+$action = $request[2];
+$post_content = json_decode($input,true);
+
+//SET PARAMETERS FOR QUERY
+$date = date('Y-m-d H:i:s');
+$current_date = date('Y-m-d');
+
+// Connect to DB (if needed for future enhancements)
+$pdo = dbConnect($dbname);
+
+if ($action == 'log'){
+
+    // Validate input data
+    if (!empty($post_content['data']) && isset($post_content['direction'])) {
+
+        $communication_data = $post_content['data'];
+        $direction = $post_content['direction']; // 'sent' or 'received'
+        $timestamp = $post_content['timestamp'] ?? $date;
+        $serial_number = $post_content['serial_number'] ?? '';
+        $maintenance_run = $post_content['maintenance_run'] ?? 0;
+
+        // Create log directory if it doesn't exist
+        $log_dir = './log/';
+        if (!is_dir($log_dir)) {
+            mkdir($log_dir, 0755, true);
+        }
+
+        // Create filename based on current date (YYYY-MM-DD)
+        $log_file = $log_dir .'serial'. $current_date . '.log';
+
+        // Format log entry
+        $log_entry = sprintf(
+            "[%s] [%s] [SN:%s] [MAINT:%d] %s: %s\n",
+            $timestamp,
+            $direction,
+            $serial_number,
+            $maintenance_run,
+            strtoupper($direction),
+            $communication_data
+        );
+
+        // Append to log file
+        if (file_put_contents($log_file, $log_entry, FILE_APPEND | LOCK_EX) !== false) {
+            // Success response
+            echo json_encode(array(
+                'status' => 'success',
+                'message' => 'Communication logged successfully',
+                'file' => $log_file
+            ));
+        } else {
+            // Error response
+            http_response_code(500);
+            echo json_encode(array(
+                'status' => 'error',
+                'message' => 'Failed to write to log file'
+            ));
+        }
+
+    } else {
+        // Invalid payload
+        http_response_code(400);
+        echo json_encode(array(
+            'status' => 'error',
+            'message' => 'Invalid payload: missing data or direction'
+        ));
+    }
+
+} else {
+    // Invalid action
+    http_response_code(400);
+    echo json_encode(array(
+        'status' => 'error',
+        'message' => 'Invalid action'
+    ));
+}
+?>