Refactor to manager-centric model, add team calendar for all users

Key changes:
- Removed office-centric model (deleted offices.py, office-rules)
- Renamed to team-rules, managers are part of their own team
- Team calendar visible to all (read-only for employees)
- Admins can have a manager assigned

frontend/pages/register.html

@@ -31,12 +31,6 @@
                     <input type="password" id="password" required autocomplete="new-password" minlength="8">
                     <small>Minimum 8 characters</small>
                 </div>
-                <div class="form-group">
-                    <label for="office">Office (optional)</label>
-                    <select id="office">
-                        <option value="">Select an office...</option>
-                    </select>
-                </div>
                 <button type="submit" class="btn btn-dark btn-full">Create Account</button>
             </form>
 
@@ -53,39 +47,17 @@
             window.location.href = '/presence';
         }
 
-        // Load offices
-        async function loadOffices() {
-            try {
-                const response = await fetch('/api/offices');
-                if (response.ok) {
-                    const offices = await response.json();
-                    const select = document.getElementById('office');
-                    offices.forEach(office => {
-                        const option = document.createElement('option');
-                        option.value = office.id;
-                        option.textContent = office.name;
-                        select.appendChild(option);
-                    });
-                }
-            } catch (error) {
-                console.error('Failed to load offices:', error);
-            }
-        }
-
-        loadOffices();
-
         document.getElementById('registerForm').addEventListener('submit', async (e) => {
             e.preventDefault();
 
             const name = document.getElementById('name').value;
             const email = document.getElementById('email').value;
             const password = document.getElementById('password').value;
-            const officeId = document.getElementById('office').value || null;
             const errorDiv = document.getElementById('errorMessage');
 
             errorDiv.innerHTML = '';
 
-            const result = await api.register(email, password, name, officeId);
+            const result = await api.register(email, password, name);
 
             if (result.success) {
                 window.location.href = '/presence';