Add full cross-platform path support

- Added automatic volume path translation in deployment (deploy.js)
- Updated FileBrowser template to use /opt/ instead of hard-coded E:/
- Migrated self-updater.js to use centralized platformPaths module
- Updated UI placeholders to use platform-neutral paths (/media/)
- All paths now automatically adapt to Windows or Linux at runtime via process.platform detection

dashcaddy-api/routes/apps/deploy.js

@@ -106,13 +106,20 @@ module.exports = function(ctx, helpers) {
         throw new Error(`[DC-203] Port conflict detected: ${conflictDetails}. Please choose a different port.`);
       }
 
+      // Translate volume paths for cross-platform compatibility
+      const translatedVolumes = (processedTemplate.docker.volumes || []).map(volume => {
+        const [hostPath, ...rest] = volume.split(':');
+        const translatedHost = platformPaths.toDockerMountPath(hostPath);
+        return rest.length > 0 ? `${translatedHost}:${rest.join(':')}` : translatedHost;
+      });
+
       const containerConfig = {
         Image: processedTemplate.docker.image,
         name: containerName,
         ExposedPorts: {},
         HostConfig: {
           PortBindings: {},
-          Binds: processedTemplate.docker.volumes || [],
+          Binds: translatedVolumes,
           RestartPolicy: { Name: 'unless-stopped' },
           LogConfig: DOCKER.LOG_CONFIG
         },