feat: major project restructure - move Django to backend dir and fix critical imports

- Restructure project: moved Django backend to backend/ directory
- Add frontend/ directory for future Next.js application
- Add shared/ directory for common resources
- Fix critical Django import errors:
  - Add missing sys.path modification for apps directory
  - Fix undefined CATEGORY_CHOICES imports in rides module
  - Fix media migration undefined references
  - Remove unused imports and f-strings without placeholders
- Install missing django-environ dependency
- Django server now runs without ModuleNotFoundError
- Update .gitignore and README for new structure
- Add pnpm workspace configuration for monorepo setup

templates/accounts/email_required.html

@@ -1,33 +0,0 @@
-{% extends "base/base.html" %}
-
-{% block title %}Email Required{% endblock %}
-
-{% block content %}
-<div class="container mx-auto px-4 py-16">
-    <div class="max-w-md mx-auto bg-white rounded-lg shadow-md p-8">
-        <h1 class="text-2xl font-bold mb-6">Email Required</h1>
-        
-        {% if error %}
-        <div class="bg-red-100 border border-red-400 text-red-700 px-4 py-3 rounded mb-4" role="alert">
-            <p>{{ error }}</p>
-        </div>
-        {% endif %}
-        
-        <p class="mb-6">Please provide your email address to complete the registration process.</p>
-        
-        <form method="post" class="space-y-4">
-            {% csrf_token %}
-            <div>
-                <label for="email" class="block text-sm font-medium text-gray-700">Email Address</label>
-                <input type="email" name="email" id="email" required
-                    class="mt-1 block w-full rounded-md border-gray-300 shadow-xs focus:border-blue-500 focus:ring-blue-500">
-            </div>
-            
-            <button type="submit"
-                class="w-full bg-blue-600 text-white py-2 px-4 rounded hover:bg-blue-700 focus:outline-hidden focus:ring-2 focus:ring-blue-500 focus:ring-offset-2">
-                Submit
-            </button>
-        </form>
-    </div>
-</div>
-{% endblock %}