refactor(shared): dedupe chat content text extraction

src/shared/chat-content.ts

@@ -0,0 +1,37 @@
+export function extractTextFromChatContent(
+  content: unknown,
+  opts?: { sanitizeText?: (text: string) => string },
+): string | null {
+  const normalize = (text: string) => text.replace(/\s+/g, " ").trim();
+
+  if (typeof content === "string") {
+    const value = opts?.sanitizeText ? opts.sanitizeText(content) : content;
+    const normalized = normalize(value);
+    return normalized ? normalized : null;
+  }
+
+  if (!Array.isArray(content)) {
+    return null;
+  }
+
+  const chunks: string[] = [];
+  for (const block of content) {
+    if (!block || typeof block !== "object") {
+      continue;
+    }
+    if ((block as { type?: unknown }).type !== "text") {
+      continue;
+    }
+    const text = (block as { text?: unknown }).text;
+    if (typeof text !== "string") {
+      continue;
+    }
+    const value = opts?.sanitizeText ? opts.sanitizeText(text) : text;
+    if (value.trim()) {
+      chunks.push(value);
+    }
+  }
+
+  const joined = normalize(chunks.join(" "));
+  return joined ? joined : null;
+}