update: bump 6 MCP packages + nixpkgs flake

- flake.lock: nixpkgs 2026-05-31 → 2026-06-16
- zotero-mcp: v0.2.2 → v0.5.0
- duckduckgo-mcp-server: 0.1.1-unstable → v0.4.0
- kindly-web-search-mcp-server: bump to latest commit + add trafilatura dep
- sabnzbd-mcp: pin to specific commit instead of refs/heads/main
- jellyfin-mcp: v2026.318.7 → v2026.604.2 (remove go.mod patch)
- nextcloud-mcp-server: v0.89.0 → v0.121.3

n8n-mcp, mcp-arr-server, pdf-reader-mcp held back:
upstream npm packages require @modelcontextprotocol/sdk versions
not yet published to npm registry

packages/jellyfin-mcp/package.nix

@@ -6,21 +6,16 @@
 
 buildGoModule rec {
   pname = "jellyfin-mcp";
-  version = "2026.318.7";
+  version = "2026.604.2";
 
   src = fetchFromGitHub {
     owner = "jaredtrent";
     repo = "jellyfin-mcp";
     tag = "v${version}";
-    hash = "sha256-/6Sy8C5+/x90ZTo74qX0agTHybsWw+Vg416GBM1PS7k=";
+    hash = "sha256-Ks54txfOAkNEWfhl5ZXEIaFzAbmCnwhHtN1+FIa7dgo=";
   };
 
-  # go.mod requires 1.25.6 but nixpkgs has 1.25.5; patch to relax
-  postPatch = ''
-    substituteInPlace go.mod --replace-fail "go 1.25.6" "go 1.25.5"
-  '';
-
-  vendorHash = "sha256-WYb+BpnKUUrgcJ0zChdTb1oB99R8bTgpSXUtjPKhL6M=";
+  vendorHash = "sha256-cDy+PpZM6xL7ur/xq81y4vlyaDnSOpGkyVV2hh8qI7o=";
 
   meta = with lib; {
     description = "MCP server for Jellyfin media server — search, playback, metadata, admin";