Inject upload size limits from settings into frontend via DIORA_CONFIG

Backend settings are now the single source of truth for EBOOK_MAX_BYTES
and BG_MAX_BYTES. A new context processor exposes them to all templates,
and base.html injects them as window.DIORA_CONFIG so app.js reads from
there instead of hardcoded values.

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

diora/context_processors.py

@@ -3,3 +3,10 @@ from django.conf import settings
 
 def build_info(request):
     return {'BUILD_TIME': getattr(settings, 'BUILD_TIME', '')}
+
+
+def upload_limits(request):
+    return {
+        'EBOOK_MAX_BYTES': getattr(settings, 'EBOOK_MAX_BYTES', 10 * 1024 * 1024),
+        'BG_MAX_BYTES': getattr(settings, 'BG_MAX_BYTES', 5 * 1024 * 1024),
+    }

diora/settings.py

@@ -62,6 +62,7 @@ TEMPLATES = [
                 'django.contrib.auth.context_processors.auth',
                 'django.contrib.messages.context_processors.messages',
                 'diora.context_processors.build_info',
+                'diora.context_processors.upload_limits',
             ],
         },
     },

static/js/app.js

@@ -2344,8 +2344,8 @@ async function uploadBackground(file) {
     alert('Only JPEG, PNG, or WebP images are allowed.');
     return;
   }
-  if (file.size > 5 * 1024 * 1024) {
-    alert('Image must be 5 MB or smaller.');
+  if (file.size > DIORA_CONFIG.bgMaxBytes) {
+    alert(`Image must be ${DIORA_CONFIG.bgMaxBytes / 1024 / 1024} MB or smaller.`);
     return;
   }
 
@@ -2884,8 +2884,8 @@ async function uploadEbook(file) {
     if (statusEl) statusEl.textContent = 'Only .epub and .pdf files are supported.';
     return;
   }
-  if (file.size > 50 * 1024 * 1024) {
-    if (statusEl) statusEl.textContent = 'File too large (max 50 MB).';
+  if (file.size > DIORA_CONFIG.ebookMaxBytes) {
+    if (statusEl) statusEl.textContent = `File too large (max ${DIORA_CONFIG.ebookMaxBytes / 1024 / 1024} MB).`;
     return;
   }
 

templates/base.html

@@ -13,6 +13,7 @@
   <link rel="apple-touch-icon" href="/static/icon-192.png">
   <link rel="stylesheet" href="/static/css/app.css">
   <title>{% block title %}diora{% endblock %}</title>
+  <script>const DIORA_CONFIG = { ebookMaxBytes: {{ EBOOK_MAX_BYTES }}, bgMaxBytes: {{ BG_MAX_BYTES }} };</script>
   {% if encrypted_bg_json %}
   <script>const ENCRYPTED_BG = {{ encrypted_bg_json|safe }};</script>
   {% endif %}