feat: Add legal links to registration views

Incorporates legal links in registration and email forms by
updating views to fetch legal documents from configuration.
Enhances compliance by ensuring users acknowledge terms of service
during account setup.

config.dist.yaml

@@ -15,3 +15,6 @@ admin:
 trust_proxy: false
 auto_join:
   - "!your_room_id:your.server"
+legal:
+  - title: "Terms of Service"
+    url: "https://matrix.your.server/_matrix/consent"

src/synapse_registration/registration/templates/registration/complete_registration.html

@@ -24,6 +24,16 @@
         <p class="help">
             Sending this form will create a Matrix account for you and reserve your username. However, you will not be able to log in until an administrator approves your registration. Please provide a reason for your registration to help us expedite the approval process.
         </p>
+        {% if legal_links %}
+            <p class="help">
+                By completing this registration, you agree to the following:
+                <ul>
+                    {% for link in legal_links %}
+                        <li><a href="{{ link.url }}">{{ link.title }}</a></li>
+                    {% endfor %}
+                </ul>
+            </p>
+        {% endif %}
         <button type="submit" class="button is-link">Complete Registration</button>
     </form>
 {% endblock content %}

src/synapse_registration/registration/templates/registration/email_form.html

@@ -16,6 +16,14 @@
         <p class="help">
             By clicking the button below, you agree that we store your email address and the IP address of the device you are using to send this request for processing your registration.
         </p>
+        {% if legal_links %}
+        <p class="help">
+            You also confirm that you have read and agree to the following documents, which govern the use of our Matrix server:
+            {% for link in legal_links %}
+                <a href="{{ link.url }}">{{ link.title }}</a>{% if not forloop.last %}, {% endif %}
+            {% endfor %}
+        </p>
+        {% endif %}
         <button type="submit" class="button is-link">Verify Email</button>
     </form>
 {% endblock content %}

src/synapse_registration/registration/views.py

@@ -45,6 +45,11 @@ class EmailInputView(FormView):
     template_name = "registration/email_form.html"
     form_class = EmailForm
 
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        context["legal_links"] = settings.LEGAL_LINKS
+        return context
+
     def form_valid(self, form):
         email = form.cleaned_data["email"]
 
@@ -114,6 +119,11 @@ class CompleteRegistrationView(FormView):
     form_class = RegistrationForm
     success_url = reverse_lazy("registration_complete")
 
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        context["legal_links"] = settings.LEGAL_LINKS
+        return context
+
     def form_valid(self, form):
         password = form.cleaned_data["password1"]
         registration_reason = form.cleaned_data["registration_reason"]

src/synapse_registration/synapse_registration/settings.py

@@ -54,6 +54,7 @@ if not ALLOWED_HOSTS:
 
 CSRF_TRUSTED_ORIGINS = [f"https://{host}" for host in ALLOWED_HOSTS]
 
+LEGAL_LINKS = config.get("legal", [])
 
 # Synapse configuration