fix(web): allow foreignObject in DOMPurify SVG, remove leftover loop code

- Add ADD_TAGS: ['foreignObject'] to all DOMPurify.sanitize calls —
  Mermaid uses foreignObject for HTML text labels inside flowchart
  nodes. The SVG profile was stripping them, causing empty boxes.
- Remove leftover sub-batch loop lines from prepared statement hoist

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

gitnexus-web/src/components/MermaidDiagram.tsx

@@ -71,7 +71,7 @@ export const MermaidDiagram = ({ code }: MermaidDiagramProps) => {
 
         // Render the diagram
         const { svg: renderedSvg } = await mermaid.render(id, code.trim());
-        const sanitizedSvg = DOMPurify.sanitize(renderedSvg, { USE_PROFILES: { svg: true, svgFilters: true } });
+        const sanitizedSvg = DOMPurify.sanitize(renderedSvg, { USE_PROFILES: { svg: true, svgFilters: true }, ADD_TAGS: ['foreignObject'] });
         setSvg(sanitizedSvg);
         setError(null);
       } catch (err) {

gitnexus-web/src/core/lbug/lbug-adapter.ts

@@ -267,12 +267,6 @@ export const loadGraphToLbug = async (
       } finally {
         await stmt.close();
       }
-
-        // Yield to event loop between sub-batches
-        if (i + SUB_BATCH_SIZE < rels.length) {
-          await new Promise(r => setTimeout(r, 0));
-        }
-      }
     }
 
     if (import.meta.env.DEV) {