Remove Nix and Home Manager setup

AGENTS.md

@@ -11,18 +11,9 @@ This repo is a single Python script (`luz-musica.py`) that:
 - Python deps: `requests`, `Pillow`.
 - Run: `python3 luz-musica.py`
 
-## Dependencies (recommended setups)
+## Dependencies
 
-### Option A (NixOS / Nix): reproducible dev shell (no pip)
-If you have Nix with flakes enabled:
-- Enter shell: `nix develop`
-- Run: `python3 luz-musica.py`
-
-Without flakes:
-- Enter shell: `nix-shell`
-- Run: `python3 luz-musica.py`
-
-### Option B (Ubuntu/Debian/etc): isolated venv (pip)
+### Ubuntu/Debian/etc: isolated venv (pip)
 Install system bits:
 - `sudo apt-get update`
 - `sudo apt-get install -y python3 python3-venv playerctl`