Configure API requests for reverse proxy setup

- Updated all API endpoints to use /rechner/api/ path
- Removed CSP localhost restriction for reverse proxy compatibility
- Added nginx proxy configuration for API requests
- Should now work through HTTPS reverse proxy

html/rechner/index.html

@@ -8,7 +8,7 @@
     script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net;
     style-src 'self' 'unsafe-inline';
     img-src 'self' data:;
-    connect-src 'self' http://localhost:3001;
+    connect-src 'self';
   ">
   <title>Rechner</title>
   

html/rechner/script.js

@@ -32,7 +32,7 @@
   const updateCoinTrackersToBackend = (trackers) => {
     console.log("Saving trackers to backend:", trackers);
     
-    fetch('http://localhost:3001/api/coinTrackers', {
+    fetch('/rechner/api/coinTrackers', {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
@@ -1182,7 +1182,7 @@
   const loadCoinTrackers = () => {
     console.log("Loading trackers from backend...");
     
-    fetch('http://localhost:3001/api/coinTrackers')
+    fetch('/rechner/api/coinTrackers')
     .then(response => {
       if (!response.ok) {
         throw new Error('Network response was not ok');
@@ -1639,7 +1639,7 @@
     document.getElementById('createBackupBtn').textContent = 'Creating backup...';
     
     // Make request to API
-    fetch(`http://localhost:3001/api/backup/create${backupName ? `?name=${encodeURIComponent(backupName)}` : ''}`)
+    fetch(`/rechner/api/backup/create${backupName ? `?name=${encodeURIComponent(backupName)}` : ''}`)
       .then(response => {
         if (!response.ok) {
           throw new Error(`Network error: ${response.status}`);
@@ -1670,7 +1670,7 @@
 
   // Function to load the list of available backups
   const loadBackupList = () => {
-    fetch('http://localhost:3001/api/backup/list')
+    fetch('/rechner/api/backup/list')
       .then(response => {
         if (!response.ok) {
           throw new Error('Network response was not ok');
@@ -1795,7 +1795,7 @@
       return;
     }
     
-    fetch(`http://localhost:3001/api/backup/restore/${filename}`)
+    fetch(`/rechner/api/backup/restore/${filename}`)
       .then(response => {
         if (!response.ok) {
           throw new Error('Network response was not ok');