Add Tailwind typography plugin for prose styling

Enables proper markdown styling with prose-invert classes.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

artdag_common/constants.py

@@ -3,7 +3,7 @@ Shared constants for Art-DAG servers.
 """
 
 # CDN URLs
-TAILWIND_CDN = "https://cdn.tailwindcss.com"
+TAILWIND_CDN = "https://cdn.tailwindcss.com?plugins=typography"
 HTMX_CDN = "https://unpkg.com/htmx.org@1.9.10"
 CYTOSCAPE_CDN = "https://cdnjs.cloudflare.com/ajax/libs/cytoscape/3.28.1/cytoscape.min.js"
 DAGRE_CDN = "https://cdnjs.cloudflare.com/ajax/libs/dagre/0.8.5/dagre.min.js"
@@ -42,6 +42,17 @@ tailwind.config = {
                     800: '#111827',
                     900: '#030712',
                 }
+            },
+            typography: {
+                invert: {
+                    css: {
+                        '--tw-prose-body': '#d1d5db',
+                        '--tw-prose-headings': '#f9fafb',
+                        '--tw-prose-links': '#60a5fa',
+                        '--tw-prose-code': '#f9fafb',
+                        '--tw-prose-pre-bg': '#1f2937',
+                    }
+                }
             }
         }
     }