chore: scaffold flake + settings + entry-point quartet

Single-source-of-truth pattern: settings.nix threads identity, host,
and remote topology into every module via specialArgs. configuration.nix
and home.nix stay thin import-lists so module composition is obvious.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

home.nix

@@ -0,0 +1,34 @@
+# lnbits-sensei — home-manager user config.
+#
+# Placeholder shell. Substantive home-manager wiring (shell, editor,
+# git identity, dev shell aliases) lands in follow-up passes once the
+# module skeleton settles.
+{
+  config,
+  pkgs,
+  lib,
+  settings,
+  osConfig,
+  ...
+}:
+
+{
+  home.username = settings.user;
+  home.homeDirectory = "/home/${settings.user}";
+
+  # State version pins the schema of files this generation produces.
+  # Match the NixOS stateVersion in configuration.nix.
+  home.stateVersion = "24.11";
+
+  # Git identity is sourced from settings.nix so it is set exactly once
+  # for the whole host.
+  programs.git = {
+    enable = true;
+    userName = settings.gitName;
+    userEmail = settings.gitEmail;
+  };
+
+  # Future passes: shell prompt, editor, lnbits dev shell aliases,
+  # direnv integration, tmux launcher, etc. Keep this file thin and
+  # delegate behaviour to modules/.
+}