feat: initialization migration to Nuxt + Backend

This commit initializes both the Nuxt frontend and the Rust backend of
the new version of phundrak.com

.envrc

@@ -1 +1,54 @@
-use nix
+#!/usr/bin/env bash
+
+if ! has nix_direnv_version || ! nix_direnv_version 3.1.0; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.1.0/direnvrc" "sha256-yMJ2OVMzrFaDPn7q8nCBZFRYpL/f0RcHzhmw/i6btJM="
+fi
+
+export DEVENV_IN_DIRENV_SHELL=true
+
+# Load .env file if present
+dotenv_if_exists
+
+watch_file flake.nix
+watch_file flake.lock
+watch_file .envrc.local
+watch_file backend/shell.nix
+watch_file frontend/shell.nix
+
+# Check if .envrc.local exists and contains a shell preference
+if [[ -f .envrc.local ]]; then
+  source .envrc.local
+fi
+
+# If no shell is specified, prompt the user interactively
+if [[ -z "$NIX_SHELL_NAME" ]]; then
+  echo ""
+  echo "🔧 Available development shells:"
+  echo "  1) frontend - Nuxt.js/Vue development environment"
+  echo "  2) backend  - Rust backend development environment"
+  echo ""
+  echo "💡 Tip: Create a .envrc.local file with 'export NIX_SHELL_NAME=frontend' to skip this prompt"
+  echo ""
+
+  # Read user input
+  read -p "Select shell (1 or 2): " choice
+
+  case $choice in
+    1|frontend)
+      NIX_SHELL_NAME=frontend
+      ;;
+    2|backend)
+      NIX_SHELL_NAME=backend
+      ;;
+    *)
+      echo "❌ Invalid choice. Please select 1 or 2."
+      return 1
+      ;;
+  esac
+
+  echo "✅ Loading ${NIX_SHELL_NAME} environment..."
+fi
+
+if ! use flake ".#${NIX_SHELL_NAME}" --no-pure-eval; then
+  echo "❌ devenv could not be built. The devenv environment was not loaded. Make the necessary changes to flake.nix and hit enter to try again." >&2
+fi