refactor(shared): reuse outbound text chunking core

src/shared/text-chunking.ts

@@ -0,0 +1,34 @@
+export function chunkTextByBreakResolver(
+  text: string,
+  limit: number,
+  resolveBreakIndex: (window: string) => number,
+): string[] {
+  if (!text) {
+    return [];
+  }
+  if (limit <= 0 || text.length <= limit) {
+    return [text];
+  }
+  const chunks: string[] = [];
+  let remaining = text;
+  while (remaining.length > limit) {
+    const window = remaining.slice(0, limit);
+    const candidateBreak = resolveBreakIndex(window);
+    const breakIdx =
+      Number.isFinite(candidateBreak) && candidateBreak > 0 && candidateBreak <= limit
+        ? candidateBreak
+        : limit;
+    const rawChunk = remaining.slice(0, breakIdx);
+    const chunk = rawChunk.trimEnd();
+    if (chunk.length > 0) {
+      chunks.push(chunk);
+    }
+    const brokeOnSeparator = breakIdx < remaining.length && /\s/.test(remaining[breakIdx]);
+    const nextStart = Math.min(remaining.length, breakIdx + (brokeOnSeparator ? 1 : 0));
+    remaining = remaining.slice(nextStart).trimStart();
+  }
+  if (remaining.length) {
+    chunks.push(remaining);
+  }
+  return chunks;
+}