Add structured sections and hierarchical navigation

Add --section flag to add/update commands for structured node content,
render sections and inline children in show, and add memory children command.

src/cli/commands/show.ts

@@ -30,6 +30,23 @@ export const showCommand = new Command('show')
     if (node.isStale) console.log(chalk.red('STALE'));
     if (node.content) console.log(`\n${node.content}`);
 
+    // Render structured sections
+    if (node.metadata?.sections && Array.isArray(node.metadata.sections)) {
+      for (const sec of node.metadata.sections) {
+        console.log(`\n${chalk.bold(`── ${sec.label} ──`)}`);
+        if (sec.body) console.log(sec.body);
+      }
+    }
+
+    // Inline children (outgoing 'contains' edges)
+    const children = conns.outgoing.filter(c => c.type === 'contains');
+    if (children.length) {
+      console.log(chalk.bold('\nChildren:'));
+      for (const c of children) {
+        console.log(`  ${c.node.id.slice(0, 8)} [${c.node.kind}] ${c.node.title}`);
+      }
+    }
+
     if (conns.outgoing.length) {
       console.log(chalk.bold('\nOutgoing:'));
       for (const c of conns.outgoing) {