fix: repoint sabnzbd-mcp to jasonpaulso fork, drop broken annas-mcp

- sabnzbd-mcp: original upstream (jmagar/sabnzbd-mcp) was deleted from
  GitHub (404). Repoint to jasonpaulso/sabnzbd-mcp fork, which preserves
  the same file layout and the /sabnzbd/api string postPatch rewrites.
- annas-mcp: remove package that was never completed (lib.fakeHash
  placeholders) and is not referenced anywhere in config-nixos. It was
  breaking 'nix flake check'.

packages/annas-mcp/package.nix

@@ -1,36 +0,0 @@
-{
-  lib,
-  buildGoModule,
-  fetchFromGitHub,
-  makeWrapper,
-}:
-
-buildGoModule rec {
-  pname = "annas-mcp";
-  version = "0.1.0-unstable-2026-06-26";
-
-  src = fetchFromGitHub {
-    owner = "iosifache";
-    repo = "annas-mcp";
-    rev = "c095963ad5d10d33da3c614495246b6ec7f680d4";
-    hash = lib.fakeHash;
-  };
-
-  vendorHash = lib.fakeHash;
-
-  nativeBuildInputs = [ makeWrapper ];
-
-  # The MCP server mode is invoked with "mcp" subcommand
-  postInstall = ''
-    wrapProgram $out/bin/annas-mcp \
-      --add-flags "mcp"
-  '';
-
-  meta = with lib; {
-    description = "MCP server and CLI tool for searching and downloading documents from Anna's Archive";
-    homepage = "https://github.com/iosifache/annas-mcp";
-    license = licenses.mit;
-    mainProgram = "annas-mcp";
-    platforms = platforms.linux;
-  };
-}