nix-packages: migrate to forgejo and add forgejo-mcp

Update nix-packages input URL from git.t-juice.club to
code.t-juice.club and add forgejo-mcp package.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flake.lock

@@ -111,18 +111,18 @@
         ]
       },
       "locked": {
-        "lastModified": 1757017925,
-        "narHash": "sha256-QC1SkvyU5nQ32lju2GYK9ozuh/JYWXfWK/T7OC6dVls=",
+        "lastModified": 1773106737,
+        "narHash": "sha256-/XL6Dn+SehMGlXvuKubNMcTk4iq2J75Z5cVO+HkIfDY=",
         "ref": "master",
-        "rev": "7723cb45020e1f561f527779540faa5901d34e4d",
-        "revCount": 31,
+        "rev": "295b0bf12ec1849564bdaa8fc2cd0f19af1a2715",
+        "revCount": 47,
         "type": "git",
-        "url": "https://git.t-juice.club/torjus/nix-packages"
+        "url": "https://code.t-juice.club/torjus/nix-packages"
       },
       "original": {
         "ref": "master",
         "type": "git",
-        "url": "https://git.t-juice.club/torjus/nix-packages"
+        "url": "https://code.t-juice.club/torjus/nix-packages"
       }
     },
     "nixpkgs": {