Implement self-contained grapho architecture with four data types

Major rewrite of grapho CLI to support:
- Type 1 (Config): grapho init <repo-url> clones NixOS config
- Type 2 (Sync): Isolated Syncthing on port 8385 (separate from system)
- Type 3 (Backup): Restic integration with systemd timer
- Type 4 (Server): Mount point for central server data

New features:
- Welcome flow on first run (detects ~/.config/grapho/grapho.toml)
- grapho setup wizard creates directory structure
- grapho sync/backup/server subcommands
- grapho status shows all four data types
- grapho doctor checks system health

Added modules/grapho.nix NixOS module:
- Configures isolated Syncthing (ports 8385, 22001, 21028)
- Sets up grapho-backup systemd service and timer
- Creates directory structure via tmpfiles
- Optional NFS server mount

Updated flake.nix:
- Export grapho NixOS module
- Add grapho CLI package (nix build .#grapho)

Documented additional Lux language limitations:
- String == comparison broken in C backend
- let _ = pattern not supported
- List literals with recursion cause segfaults

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

flake.nix

@@ -14,6 +14,11 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
+    lux = {
+      url = "path:/home/blu/src/lux";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     # Optional: Neovim distribution
     # nixvim = {
     #   url = "github:nix-community/nixvim";
@@ -21,7 +26,7 @@
     # };
   };
 
-  outputs = { self, nixpkgs, home-manager, sops-nix, ... }@inputs:
+  outputs = { self, nixpkgs, home-manager, sops-nix, lux, ... }@inputs:
     let
       # Supported systems
       supportedSystems = [ "x86_64-linux" "aarch64-linux" ];
@@ -37,6 +42,7 @@
 
       # Shared modules for all hosts
       sharedModules = [
+        ./modules/grapho.nix
         ./modules/nb.nix
         ./modules/syncthing.nix
         ./modules/backup.nix
@@ -60,6 +66,39 @@
         };
 
     in {
+      # Grapho CLI package
+      packages = forAllSystems (system:
+        let
+          pkgs = nixpkgsFor.${system};
+          luxPkg = lux.packages.${system}.default;
+        in {
+          grapho = pkgs.stdenv.mkDerivation {
+            pname = "grapho";
+            version = "0.1.0";
+            src = ./cli;
+
+            nativeBuildInputs = [ luxPkg pkgs.gcc ];
+
+            buildPhase = ''
+              ${luxPkg}/bin/lux compile grapho.lux -o grapho
+            '';
+
+            installPhase = ''
+              mkdir -p $out/bin
+              cp grapho $out/bin/
+            '';
+
+            meta = {
+              description = "Personal data infrastructure CLI";
+              homepage = "https://github.com/user/grapho";
+              license = pkgs.lib.licenses.mit;
+            };
+          };
+
+          default = self.packages.${system}.grapho;
+        }
+      );
+
       # NixOS configurations
       # Uncomment and customize for your hosts:
       #
@@ -132,7 +171,9 @@
           default = pkgs.mkShell {
             name = "unsbs-dev";
 
-            packages = with pkgs; [
+            packages = [
+              lux.packages.${system}.default
+            ] ++ (with pkgs; [
               # Tier 2: Notes & Sync
               nb              # Notebook CLI
               syncthing       # File sync
@@ -159,7 +200,7 @@
               # Nix tools
               nil             # Nix LSP
               nixpkgs-fmt     # Nix formatter
-            ];
+            ]);
 
             shellHook = ''
               printf '\033[1m%s\033[0m\n' "Ultimate Notetaking, Sync & Backup System"
@@ -175,6 +216,7 @@
 
       # Export modules for use in other flakes
       nixosModules = {
+        grapho = import ./modules/grapho.nix;
         nb = import ./modules/nb.nix;
         syncthing = import ./modules/syncthing.nix;
         backup = import ./modules/backup.nix;