chore: migrate to Nix flakes, remove Docker and legacy configs

Remove all Docker files, Vercel config, Verdaccio, and old CI workflow.
Standardize on nodejs_22 across devShell and nix build helpers.
Update CI to build all packages and push to Cachix on merge to develop.

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

nix/example-infrastructure.nix

@@ -1,89 +0,0 @@
-# Example: How to use in imphnen-infrastructure
-#
-# In your imphnen-infrastructure flake.nix:
-#
-# {
-#   inputs = {
-#     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-#     imphnen-frontend = {
-#       url = "github:your-org/imphnen-frontend-service";
-#       # Or use local path during development:
-#       # url = "path:/path/to/imphnen-frontend-service";
-#     };
-#   };
-#
-#   outputs = { self, nixpkgs, imphnen-frontend, ... }: {
-#     nixosConfigurations.your-server = nixpkgs.lib.nixosSystem {
-#       system = "x86_64-linux";
-#       modules = [
-#         # Import all modules at once
-#         imphnen-frontend.nixosModules.all
-#
-#         # Or import individually:
-#         # imphnen-frontend.nixosModules.landing
-#         # imphnen-frontend.nixosModules.backoffice
-#
-#         ./your-server-config.nix
-#       ];
-#     };
-#   };
-# }
-#
-# Then in your-server-config.nix:
-
-{ config, pkgs, ... }:
-
-{
-  # Enable Landing (Next.js) - runs as systemd service
-  services.imphnen-landing = {
-    enable = true;
-    port = 3000;
-    hostname = "0.0.0.0";
-    openFirewall = true;
-    # environmentFile = /run/secrets/landing-env;  # For secrets
-  };
-
-  # Enable Backoffice (Static) - served by nginx
-  services.imphnen-backoffice = {
-    enable = true;
-    domain = "backoffice.imphnen.dev";
-    enableSSL = true;
-  };
-
-  # Enable Gacha (Static)
-  services.imphnen-gacha = {
-    enable = true;
-    domain = "gacha.imphnen.dev";
-    enableSSL = true;
-  };
-
-  # Enable Dimentorin (Static)
-  services.imphnen-dimentorin = {
-    enable = true;
-    domain = "dimentorin.imphnen.dev";
-    enableSSL = true;
-  };
-
-  # Enable Hackathon (Static)
-  services.imphnen-hackathon = {
-    enable = true;
-    domain = "hackathon.imphnen.dev";
-    enableSSL = true;
-  };
-
-  # Nginx reverse proxy for landing (if needed)
-  services.nginx.virtualHosts."imphnen.dev" = {
-    forceSSL = true;
-    enableACME = true;
-    locations."/" = {
-      proxyPass = "http://127.0.0.1:3000";
-      proxyWebsockets = true;
-    };
-  };
-
-  # Enable ACME for SSL
-  security.acme = {
-    acceptTerms = true;
-    defaults.email = "admin@imphnen.dev";
-  };
-}

nix/landing.nix

@@ -10,8 +10,7 @@ pkgs.buildNpmPackage {
   makeCacheWritable = true;
 
   nativeBuildInputs = with pkgs; [
-    nodejs
-    nodePackages.npm
+    nodejs_22
     python3  # Required for node-gyp (sharp, etc.)
   ];
 
@@ -48,7 +47,7 @@ pkgs.buildNpmPackage {
     cat > $out/bin/imphnen-landing <<EOF
     #!${pkgs.bash}/bin/bash
     cd $out/share/landing
-    exec ${pkgs.nodejs}/bin/node --jitless apps/landing/server.js "\$@"
+    exec ${pkgs.nodejs_22}/bin/node --jitless apps/landing/server.js "\$@"
     EOF
     chmod +x $out/bin/imphnen-landing
 

nix/mkViteApp.nix

@@ -12,8 +12,7 @@ pkgs.buildNpmPackage {
   makeCacheWritable = true;
 
   nativeBuildInputs = with pkgs; [
-    nodejs
-    nodePackages.npm
+    nodejs_22
     util-linux  # For script command to create pseudo-terminal
   ];