Add Navidrome and system services modules

Configure Navidrome settings (MusicFolder, Port 4533, Address 0.0.0.0),
open firewall and create tmpfiles entry for the music directory.

Enable system services: weekly fstrim, zram swap (zstd), Avahi mDNS,
psd,
fwupd, earlyoom and plocate

modules/navidrome.nix

@@ -0,0 +1,54 @@
+# modules/navidrome.nix
+# Self-hosted music streaming server
+{ config, pkgs, lib, ... }:
+
+{
+  # ═══════════════════════════════════════════════════════════════
+  # NAVIDROME MUSIC SERVER
+  # ═══════════════════════════════════════════════════════════════
+  services.navidrome = {
+    enable = true;
+
+    settings = {
+      # Music library location
+      MusicFolder = "/home/pinj/Music";
+
+      # Server settings
+      Address = "0.0.0.0";
+      Port = 4533;
+
+      # UI settings
+      UIWelcomeMessage = "Welcome to Navidrome!";
+
+      # Enable transcoding (requires ffmpeg)
+      EnableTranscodingConfig = true;
+
+      # Scan settings
+      ScanSchedule = "@every 1h";    # Rescan library every hour
+      
+      # Last.fm scrobbling (configure in UI after setup)
+      LastFM.Enabled = true;
+
+      # Enable sharing features
+      EnableSharing = true;
+
+      # Enable covers from external sources
+      CoverArtPriority = "cover.*, folder.*, front.*, embedded, external";
+
+      # Session timeout (24 hours)
+      SessionTimeout = "24h";
+
+      # Enable Prometheus metrics (optional)
+      # Prometheus.Enabled = true;
+    };
+  };
+
+  # Open firewall for Navidrome
+  # Remove or comment out if you only access locally
+  networking.firewall.allowedTCPPorts = [ 4533 ];
+
+  # Ensure music directory exists and has correct permissions
+  systemd.tmpfiles.rules = [
+    "d /home/pinj/Music 0755 pinj users -"
+  ];
+}