feat: Flow-oriented exploration with entry point identification

Update Claude prompt to identify the entry point and return symbols in
execution order. The graph now centers on the entry point and auto-opens
its detail panel, giving users a clear starting point to trace the flow.

- Claude returns {entry, flow} instead of flat array
- Entry point is auto-selected and centered on load
- Detail panel opens immediately for the entry point
- Prompt asks for max 8-10 symbols in execution order

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

src/visualizer/public/index.html

@@ -1414,7 +1414,7 @@
         }
         addSubgraph(data.nodes, data.edges);
 
-        // Highlight root/entry-point nodes
+        // Highlight root nodes, with entry point getting special treatment
         if (data.roots && data.roots.length > 0) {
           for (const rootId of data.roots) {
             const ele = cy.getElementById(rootId);
@@ -1423,6 +1423,19 @@
         }
 
         runLayout();
+
+        // Center on entry point if available
+        if (data.entryPoint) {
+          const entryEle = cy.getElementById(data.entryPoint);
+          if (entryEle.length > 0) {
+            entryEle.select();
+            setTimeout(() => {
+              cy.animate({ center: { eles: entryEle } }, { duration: 400 });
+              showNodeDetails(data.entryPoint);
+            }, 350);
+          }
+        }
+
         const source = data.usedClaude ? ' (via Claude)' : '';
         showToast(`Found ${data.nodes.length} related symbols${source}`);
       } catch (err) {