feat(06-01): add countWordsInMinimalBody util for reading-time computation

- Pure AST traversal of @nuxt/content v3 minimal body shape
- Skips code and pre tags (code snippets are not readable prose)
- Zero dependency, zero import, reused by Nitro hook

app/utils/countWords.ts

@@ -0,0 +1,34 @@
+/**
+ * Count words in a @nuxt/content v3 "minimal" body AST.
+ * Ignores code and pre tags (code snippets are not "readable" for reading-time purposes).
+ *
+ * Body shape (v3): { type: 'minimal', value: MinimalNode[] }
+ * MinimalNode = string | [tag: string, attrs: object, ...children: MinimalNode[]]
+ *
+ * Used by server/plugins/reading-time.ts at content:file:afterParse.
+ */
+export function countWordsInMinimalBody(body: unknown): number {
+  let count = 0
+
+  const visit = (node: unknown): void => {
+    if (typeof node === 'string') {
+      const trimmed = node.trim()
+      if (trimmed) count += trimmed.split(/\s+/).length
+      return
+    }
+    if (Array.isArray(node)) {
+      const tag = node[0]
+      // Skip code/pre — not counted as reading content
+      if (tag === 'code' || tag === 'pre') return
+      // children start at index 2 (index 0 = tag, index 1 = attrs)
+      for (let i = 2; i < node.length; i++) visit(node[i])
+    }
+  }
+
+  const body_ = body as { type?: string; value?: unknown[] } | undefined
+  if (body_?.value && Array.isArray(body_.value)) {
+    for (const node of body_.value) visit(node)
+  }
+
+  return count
+}