Add IPFS CID display with public gateway links

- Cache detail page shows IPFS section with CID and links to
  ipfs.io, dweb.link, Cloudflare, and Pinata gateways
- Media list cards show purple "IPFS" badge for items with CID
- JSON API response includes ipfs_cid field

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

server.py

@@ -1714,6 +1714,10 @@ async def cache_detail(content_hash: str, request: Request):
         elif file_size > 1024:
             size_str = f"{file_size/1024:.1f} KB"
 
+        # Get IPFS CID from database
+        cache_item = await database.get_cache_item(content_hash)
+        ipfs_cid = cache_item.get("ipfs_cid") if cache_item else None
+
         # Build media display HTML
         if media_type == "video":
             video_src = video_src_for_request(content_hash, request)
@@ -1770,7 +1774,47 @@ async def cache_detail(content_hash: str, request: Request):
                     </div>
                 </div>
             </div>
+            '''
 
+        # Add IPFS section if we have a CID
+        if ipfs_cid:
+            content += f'''
+            <div class="border-t border-dark-500 pt-6 mt-6">
+                <h2 class="text-lg font-semibold text-white mb-4">IPFS</h2>
+                <div class="bg-dark-600 rounded-lg p-4 mb-4">
+                    <div class="text-sm text-gray-400 mb-1">Content Identifier (CID)</div>
+                    <div class="font-mono text-xs text-gray-200 break-all">{ipfs_cid}</div>
+                </div>
+                <div class="text-sm text-gray-400 mb-2">Public Gateways:</div>
+                <div class="flex flex-wrap gap-2">
+                    <a href="https://ipfs.io/ipfs/{ipfs_cid}" target="_blank" rel="noopener"
+                       class="px-3 py-1 bg-purple-600 hover:bg-purple-700 text-white text-sm rounded-lg transition-colors">
+                        ipfs.io
+                    </a>
+                    <a href="https://dweb.link/ipfs/{ipfs_cid}" target="_blank" rel="noopener"
+                       class="px-3 py-1 bg-purple-600 hover:bg-purple-700 text-white text-sm rounded-lg transition-colors">
+                        dweb.link
+                    </a>
+                    <a href="https://cloudflare-ipfs.com/ipfs/{ipfs_cid}" target="_blank" rel="noopener"
+                       class="px-3 py-1 bg-purple-600 hover:bg-purple-700 text-white text-sm rounded-lg transition-colors">
+                        Cloudflare
+                    </a>
+                    <a href="https://gateway.pinata.cloud/ipfs/{ipfs_cid}" target="_blank" rel="noopener"
+                       class="px-3 py-1 bg-purple-600 hover:bg-purple-700 text-white text-sm rounded-lg transition-colors">
+                        Pinata
+                    </a>
+                </div>
+            </div>
+            '''
+        else:
+            content += '''
+            <div class="border-t border-dark-500 pt-6 mt-6">
+                <h2 class="text-lg font-semibold text-white mb-4">IPFS</h2>
+                <div class="text-gray-400 text-sm">Not yet uploaded to IPFS</div>
+            </div>
+            '''
+
+        content += f'''
             <!-- Metadata Section -->
             <div class="border-t border-dark-500 pt-6 mt-6" id="metadata-section"
                  hx-get="/cache/{content_hash}/meta-form" hx-trigger="load" hx-swap="innerHTML">
@@ -1783,12 +1827,15 @@ async def cache_detail(content_hash: str, request: Request):
 
     # JSON response - return metadata
     meta = await database.load_item_metadata(content_hash, ctx.actor_id if ctx else None)
+    cache_item = await database.get_cache_item(content_hash)
+    ipfs_cid = cache_item.get("ipfs_cid") if cache_item else None
     file_size = cache_path.stat().st_size
     media_type = detect_media_type(cache_path)
     return {
         "content_hash": content_hash,
         "size": file_size,
         "media_type": media_type,
+        "ipfs_cid": ipfs_cid,
         "meta": meta
     }
 
@@ -3510,6 +3557,11 @@ async def ui_media_list(
         cache_path = get_cache_path(content_hash)
         media_type = detect_media_type(cache_path) if cache_path else "unknown"
 
+        # Check IPFS status
+        cache_item = await database.get_cache_item(content_hash)
+        ipfs_cid = cache_item.get("ipfs_cid") if cache_item else None
+        ipfs_badge = '<span class="px-2 py-1 bg-purple-600 text-white text-xs font-medium rounded-full" title="On IPFS">IPFS</span>' if ipfs_cid else ''
+
         # Format size
         size = item["size"]
         if size > 1024*1024:
@@ -3523,7 +3575,10 @@ async def ui_media_list(
         <a href="/ui/cache/{content_hash}" class="block">
         <div class="bg-dark-700 rounded-lg p-4 hover:bg-dark-600 transition-colors">
             <div class="flex items-center justify-between gap-2 mb-3">
-                <span class="px-2 py-1 bg-blue-600 text-white text-xs font-medium rounded-full">{media_type}</span>
+                <div class="flex items-center gap-2">
+                    <span class="px-2 py-1 bg-blue-600 text-white text-xs font-medium rounded-full">{media_type}</span>
+                    {ipfs_badge}
+                </div>
                 <span class="text-xs text-gray-400">{size_str}</span>
             </div>
             <div class="text-xs text-gray-400 font-mono mb-3 truncate">{content_hash[:24]}...</div>