feat(nix): add Nextcloud Claude Bot integration

- Added configuration for Nextcloud Claude Bot, including NixOS module, secrets management, and example setup files.
- Introduced a Python-based HTTP server for handling webhook events and interacting with Nextcloud Talk.
- Integrated necessary dependencies and systemd service for seamless operation.

systems/x86_64-linux/mx/nextcloud-claude-bot/example-config.nix

@@ -0,0 +1,80 @@
+# Example NixOS configuration for the Nextcloud Claude Bot
+# Add this to your configuration.nix or a separate module
+
+{ config, pkgs, ... }:
+
+{
+  imports = [
+    ./nextcloud-claude-bot/module.nix
+  ];
+
+  # Install Claude Code CLI
+  # Note: You'll need to either:
+  # 1. Use the official package if available in nixpkgs
+  # 2. Package it yourself
+  # 3. Use a binary wrapper
+  
+  # Option 1: If claude-code is in nixpkgs (check latest state)
+  # environment.systemPackages = [ pkgs.claude-code ];
+  
+  # Option 2: Manual binary installation wrapper
+  nixpkgs.overlays = [
+    (final: prev: {
+      claude-code = final.writeShellScriptBin "claude" ''
+        # Assumes claude is installed via npm globally or similar
+        exec ${final.nodejs}/bin/node /opt/claude-code/cli.js "$@"
+      '';
+    })
+  ];
+
+  # Create bot secret
+  # Generate with: openssl rand -hex 32
+  # Store in a file, e.g., /var/secrets/nextcloud-claude-bot
+  
+  services.nextcloud-claude-bot = {
+    enable = true;
+    port = 8085;
+    host = "127.0.0.1";
+    
+    nextcloudUrl = "https://cloud.example.com";
+    botSecretFile = "/var/secrets/nextcloud-claude-bot";
+    
+    # Only allow specific users
+    allowedUsers = [ "harald" ];
+    
+    # Claude settings
+    maxTokens = 4096;
+    timeout = 120;
+    
+    # Optional system prompt
+    systemPrompt = ''
+      Du bist ein hilfreicher Assistent. Antworte auf Deutsch, 
+      es sei denn der Nutzer schreibt auf Englisch.
+    '';
+  };
+
+  # Ensure secrets directory exists with proper permissions
+  systemd.tmpfiles.rules = [
+    "d /var/secrets 0750 root root -"
+  ];
+
+  # If Nextcloud runs locally, bot can stay on localhost.
+  # If you need external access (e.g., Nextcloud on different server):
+  services.nginx.virtualHosts."cloud.example.com" = {
+    # ... your existing Nextcloud config ...
+    
+    locations."/_claude-bot/" = {
+      proxyPass = "http://127.0.0.1:8085/";
+      extraConfig = ''
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        
+        # Only allow from Nextcloud itself
+        allow 127.0.0.1;
+        deny all;
+      '';
+    };
+  };
+}