fix: Docker build and runtime fixes

- Fix duplicate 'signature' variable in webhooks.ts
- Add Prisma binary target for Alpine Linux
- Fix tsconfig path alias (@/* -> ./src/*)
- Add missing next-themes dependency
- Add build args for NEXT_PUBLIC_* env vars
- Fix SSR issues with zustand and providers
- Add providers-wrapper with dynamic ssr:false import
- Add SSL certs and public dir for nginx
- Update Dockerfiles for proper Prisma engine handling

backend/src/routes/webhooks.ts

@@ -26,11 +26,11 @@ function verifyWebhookSignature(payload: string, signature: string): boolean {
 // Tautulli webhook endpoint
 router.post('/tautulli',
   asyncHandler(async (req, res) => {
-    const signature = req.headers['x-tautulli-signature'] as string;
+    const webhookSignature = req.headers['x-tautulli-signature'] as string;
     const payload = JSON.stringify(req.body);
     
     // Verify signature if configured
-    if (WEBHOOK_SECRET && signature && !verifyWebhookSignature(payload, signature)) {
+    if (WEBHOOK_SECRET && webhookSignature && !verifyWebhookSignature(payload, webhookSignature)) {
       return res.status(401).json({ error: 'Invalid signature' });
     }