feat: production routing support for subdomain and custom domain modes

Double-mount store routes at /store/* and /store/{store_code}/* so the
same handlers work in dev path-based, prod path-based, prod subdomain,
and prod custom-domain modes.  Wire StorePlatform.custom_subdomain into
StoreContextMiddleware for per-platform subdomain overrides.  Add admin
custom-domain management UI, fix stale /shop/ reset link, add
/merchants/ to reserved paths, and server-render window.STORE_CODE for
JS that previously parsed the URL.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/templates/store/base.html

@@ -56,6 +56,7 @@
 
     <!-- 1.5: Store Configuration (resolved via PlatformSettingsService) -->
     <script>
+        window.STORE_CODE = '{{ store_code | default("") }}';
         window.STORE_CONFIG = {
             locale: '{{ storefront_locale }}',
             currency: '{{ storefront_currency }}',

app/templates/store/errors/400.html

@@ -15,7 +15,7 @@
 
 <div class="action-buttons">
     <a href="javascript:history.back()" class="btn btn-primary">Go Back</a>
-    <a href="/store/dashboard" class="btn btn-secondary">Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-secondary">Dashboard</a>
 </div>
 
 {% if show_debug %}
@@ -39,6 +39,6 @@
 {% endif %}
 
 <div class="support-link">
-    Need help? <a href="/store/support">Contact Support</a>
+    Need help? <a href="/store/{{ store_code }}/support">Contact Support</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/401.html

@@ -14,8 +14,8 @@
 <div class="error-code">Error Code: {{ error_code }}</div>
 
 <div class="action-buttons">
-    <a href="/store/login" class="btn btn-primary">Log In</a>
-    <a href="/store/dashboard" class="btn btn-secondary">Dashboard</a>
+    <a href="/store/{{ store_code }}/login" class="btn btn-primary">Log In</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-secondary">Dashboard</a>
 </div>
 
 {% if show_debug %}
@@ -39,6 +39,6 @@
 {% endif %}
 
 <div class="support-link">
-    Having login issues? <a href="/store/support">Contact Support</a>
+    Having login issues? <a href="/store/{{ store_code }}/support">Contact Support</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/403.html

@@ -14,7 +14,7 @@
 <div class="error-code">Error Code: {{ error_code }}</div>
 
 <div class="action-buttons">
-    <a href="/store/dashboard" class="btn btn-primary">Go to Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-primary">Go to Dashboard</a>
     <a href="javascript:history.back()" class="btn btn-secondary">Go Back</a>
 </div>
 
@@ -39,6 +39,6 @@
 {% endif %}
 
 <div class="support-link">
-    Need elevated permissions? <a href="/store/support">Contact Your Manager</a>
+    Need elevated permissions? <a href="/store/{{ store_code }}/support">Contact Your Manager</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/404.html

@@ -14,7 +14,7 @@
 <div class="error-code">Error Code: {{ error_code }}</div>
 
 <div class="action-buttons">
-    <a href="/store/dashboard" class="btn btn-primary">Go to Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-primary">Go to Dashboard</a>
     <a href="javascript:history.back()" class="btn btn-secondary">Go Back</a>
 </div>
 
@@ -39,6 +39,6 @@
 {% endif %}
 
 <div class="support-link">
-    Can't find what you're looking for? <a href="/store/support">Contact Support</a>
+    Can't find what you're looking for? <a href="/store/{{ store_code }}/support">Contact Support</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/422.html

@@ -29,7 +29,7 @@
 
 <div class="action-buttons">
     <a href="javascript:history.back()" class="btn btn-primary">Go Back</a>
-    <a href="/store/dashboard" class="btn btn-secondary">Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-secondary">Dashboard</a>
 </div>
 
 {% if show_debug %}
@@ -53,6 +53,6 @@
 {% endif %}
 
 <div class="support-link">
-    Still having issues? <a href="/store/support">Contact Support</a>
+    Still having issues? <a href="/store/{{ store_code }}/support">Contact Support</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/429.html

@@ -23,7 +23,7 @@
 
 <div class="action-buttons">
     <a href="javascript:location.reload()" class="btn btn-primary">Retry</a>
-    <a href="/store/dashboard" class="btn btn-secondary">Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-secondary">Dashboard</a>
 </div>
 
 {% if show_debug %}
@@ -47,6 +47,6 @@
 {% endif %}
 
 <div class="support-link">
-    Experiencing persistent rate limits? <a href="/store/support">Contact Support</a>
+    Experiencing persistent rate limits? <a href="/store/{{ store_code }}/support">Contact Support</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/500.html

@@ -14,7 +14,7 @@
 <div class="error-code">Error Code: {{ error_code }}</div>
 
 <div class="action-buttons">
-    <a href="/store/dashboard" class="btn btn-primary">Go to Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-primary">Go to Dashboard</a>
     <a href="javascript:location.reload()" class="btn btn-secondary">Retry</a>
 </div>
 
@@ -39,6 +39,6 @@
 {% endif %}
 
 <div class="support-link">
-    Issue persisting? <a href="/store/support">Report this error</a>
+    Issue persisting? <a href="/store/{{ store_code }}/support">Report this error</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/502.html

@@ -15,7 +15,7 @@
 
 <div class="action-buttons">
     <a href="javascript:location.reload()" class="btn btn-primary">Retry</a>
-    <a href="/store/dashboard" class="btn btn-secondary">Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-secondary">Dashboard</a>
 </div>
 
 {% if show_debug %}
@@ -39,6 +39,6 @@
 {% endif %}
 
 <div class="support-link">
-    Service unavailable for extended period? <a href="/store/support">Check Status</a>
+    Service unavailable for extended period? <a href="/store/{{ store_code }}/support">Check Status</a>
 </div>
-{% endblock %}
+{% endblock %}

app/templates/store/errors/base.html

@@ -185,7 +185,7 @@
 
         <div class="action-buttons">
             {% block action_buttons %}
-            <a href="/store/dashboard" class="btn btn-primary">Go to Dashboard</a>
+            <a href="/store/{{ store_code }}/dashboard" class="btn btn-primary">Go to Dashboard</a>
             <a href="javascript:history.back()" class="btn btn-secondary">Go Back</a>
             {% endblock %}
         </div>
@@ -214,10 +214,10 @@
 
         <div class="support-link">
             {% block support_link %}
-            Need help? <a href="/store/support">Contact Store Support</a>
+            Need help? <a href="/store/{{ store_code }}/support">Contact Store Support</a>
             {% endblock %}
         </div>
         {% endblock %}
     </div>
 </body>
-</html>
+</html>

app/templates/store/errors/generic.html

@@ -12,7 +12,7 @@
 <div class="error-code">Error Code: {{ error_code }}</div>
 
 <div class="action-buttons">
-    <a href="/store/dashboard" class="btn btn-primary">Go to Dashboard</a>
+    <a href="/store/{{ store_code }}/dashboard" class="btn btn-primary">Go to Dashboard</a>
     <a href="javascript:history.back()" class="btn btn-secondary">Go Back</a>
 </div>
 
@@ -37,6 +37,6 @@
 {% endif %}
 
 <div class="support-link">
-    Need assistance? <a href="/store/support">Contact Support</a>
+    Need assistance? <a href="/store/{{ store_code }}/support">Contact Support</a>
 </div>
-{% endblock %}
+{% endblock %}