Add MCP server packages: annas, bitwarden, email, namecheap, navidrome, ovhcloud, slskd

Packages MCP servers currently used by Hermes that were not yet in this
repo. Real hashes computed via nix build on wilkes; nix flake check passes.

- annas-mcp: Go, buildGoModule (re-added, previously dropped as broken)
- bitwarden-mcp: npm @bitwarden/mcp-server
- mcp-email-server: Python, buildPythonApplication
- namecheap-mcp: npm namecheap-api-mcp
- navidrome-mcp: npm navidrome-mcp
- ovhcloud-mcp: npm from GitHub, tsc build step
- slskd-mcp: Python, fastmcp wrapper

packages/namecheap-mcp/package.nix

@@ -0,0 +1,33 @@
+{
+  lib,
+  buildNpmPackage,
+  fetchzip,
+}:
+
+buildNpmPackage rec {
+  pname = "namecheap-mcp";
+  version = "1.0.1";
+
+  src = fetchzip {
+    # npm package is "namecheap-api-mcp"; pname is the Nix attr name.
+    url = "https://registry.npmjs.org/namecheap-api-mcp/-/namecheap-api-mcp-${version}.tgz";
+    hash = "sha256-+/MwPgrxJiWmObkLF30YqXWGwesbp98qzGiv/W86WYw=";
+  };
+
+  npmDepsHash = "sha256-l0i/zzy3I29ilF8vZMBrTlBQdvrISC9Vr/iQJXDVKmw=";
+
+  postPatch = ''
+    cp ${./package-lock.json} package-lock.json
+  '';
+
+  # dist/ is already built in the npm tarball
+  dontNpmBuild = true;
+
+  meta = with lib; {
+    description = "Namecheap API MCP server - DNS, domains, contacts, and registrar lock management";
+    homepage = "https://github.com/lanternrow/namecheap-api-mcp";
+    license = licenses.mit;
+    mainProgram = "namecheap-api-mcp";
+    platforms = platforms.all;
+  };
+}