Add optional no-auth mode for simplified local testing

This update introduces an AUTH_MODE configuration that allows developers
to easily test the application locally without requiring Entra ID setup.

Changes:
- Add AUTH_MODE environment variable (entra/none) to .env.example and config
- Update auth decorators to support both authentication modes
- Create role selection page for no-auth mode (admin/user choice)
- Modify auth routes to conditionally use MSAL only in Entra ID mode
- Update UserModel to support mock test users with string IDs
- Add visual indicator in navbar when running in no-auth mode

Benefits:
- Zero Azure AD configuration needed for local development
- Quick testing of role-based features (admin vs user)
- Existing Entra ID functionality remains unchanged
- Simple toggle via environment variable

To use no-auth mode, set AUTH_MODE=none in .env file.
For production, use AUTH_MODE=entra (default).

src/app/templates/layout.html

@@ -72,6 +72,15 @@
                     {% endif %}
                 </ul>
                 <ul class="navbar-nav ms-auto">
+                    {% if config.AUTH_MODE == 'none' %}
+                    <li class="nav-item">
+                        <span class="nav-link">
+                            <span class="badge bg-warning text-dark">
+                                <i class="bi bi-shield-lock"></i> No Auth Mode
+                            </span>
+                        </span>
+                    </li>
+                    {% endif %}
                     {% if session.user %}
                     <li class="nav-item dropdown">
                         <a class="nav-link dropdown-toggle" href="#" id="userDropdown" role="button" data-bs-toggle="dropdown">

src/app/templates/select_role.html

@@ -0,0 +1,105 @@
+{% extends "layout.html" %}
+
+{% block title %}Select Role - KCAP Demo Server{% endblock %}
+
+{% block extra_css %}
+<style>
+    .role-selection-container {
+        max-width: 600px;
+        margin: 100px auto;
+    }
+    .role-card {
+        transition: all 0.3s ease;
+        cursor: pointer;
+        border: 2px solid transparent;
+    }
+    .role-card:hover {
+        transform: translateY(-5px);
+        border-color: #0d6efd;
+        box-shadow: 0 4px 12px rgba(0,0,0,0.15);
+    }
+    .role-icon {
+        font-size: 3rem;
+        margin-bottom: 1rem;
+    }
+    .auth-mode-badge {
+        position: fixed;
+        top: 80px;
+        right: 20px;
+        z-index: 1000;
+    }
+</style>
+{% endblock %}
+
+{% block content %}
+<span class="badge bg-warning text-dark auth-mode-badge">
+    <i class="bi bi-shield-lock"></i> No Auth Mode
+</span>
+
+<div class="role-selection-container">
+    <div class="text-center mb-4">
+        <h2>Welcome to KCAP Demo Server</h2>
+        <p class="text-muted">Select your role to continue</p>
+        <small class="text-muted">
+            <i class="bi bi-info-circle"></i> Running in no-auth mode for local testing
+        </small>
+    </div>
+
+    <div class="row g-4">
+        <div class="col-md-6">
+            <div class="card role-card h-100 text-center" onclick="selectRole('admin')">
+                <div class="card-body p-4">
+                    <div class="role-icon text-danger">
+                        <i class="bi bi-shield-fill-check"></i>
+                    </div>
+                    <h4>Admin</h4>
+                    <p class="text-muted mb-0">
+                        Full access to all tenants, server settings, and user management
+                    </p>
+                    <ul class="list-unstyled text-start mt-3">
+                        <li><i class="bi bi-check-circle-fill text-success"></i> Manage all tenants</li>
+                        <li><i class="bi bi-check-circle-fill text-success"></i> Server settings</li>
+                        <li><i class="bi bi-check-circle-fill text-success"></i> User management</li>
+                    </ul>
+                </div>
+            </div>
+        </div>
+
+        <div class="col-md-6">
+            <div class="card role-card h-100 text-center" onclick="selectRole('user')">
+                <div class="card-body p-4">
+                    <div class="role-icon text-primary">
+                        <i class="bi bi-person-circle"></i>
+                    </div>
+                    <h4>User</h4>
+                    <p class="text-muted mb-0">
+                        Access to assigned tenants only
+                    </p>
+                    <ul class="list-unstyled text-start mt-3">
+                        <li><i class="bi bi-check-circle-fill text-success"></i> Assigned tenants</li>
+                        <li><i class="bi bi-x-circle-fill text-danger"></i> Server settings</li>
+                        <li><i class="bi bi-x-circle-fill text-danger"></i> User management</li>
+                    </ul>
+                </div>
+            </div>
+        </div>
+    </div>
+
+    <div class="alert alert-info mt-4" role="alert">
+        <i class="bi bi-lightbulb"></i>
+        <strong>Testing Mode:</strong> This selection is temporary and only for local development.
+        To use Entra ID authentication, set <code>AUTH_MODE=entra</code> in your .env file.
+    </div>
+</div>
+
+<form id="roleForm" method="POST" action="{{ url_for('auth.select_role') }}" style="display: none;">
+    <input type="hidden" name="role" id="roleInput">
+</form>
+
+<script>
+function selectRole(role) {
+    document.getElementById('roleInput').value = role;
+    document.getElementById('roleForm').submit();
+}
+</script>
+{% endblock %}