feat: Initial clean release of CHM

packages/lib/services/ai/utils/extractReasoning.ts

@@ -0,0 +1,37 @@
+// Some models emit reasoning inline instead of in a separate field. Gemma's
+// pair is asymmetric, so generic special-token filters miss it.
+const markerPairs = [
+	{ open: '<|channel>', close: '<channel|>' },
+	{ open: '<think>', close: '</think>' },
+	{ open: '<thinking>', close: '</thinking>' },
+];
+
+interface ExtractedReasoning {
+	text: string;
+	reasoning: string;
+}
+
+// Only a leading marker counts: anything later is the model talking *about*
+// these tags, and stripping it would corrupt the answer.
+const extractReasoning = (content: string): ExtractedReasoning => {
+	if (!content) return { text: '', reasoning: '' };
+
+	const trimmed = content.trimStart();
+	const pair = markerPairs.find(candidate => trimmed.startsWith(candidate.open));
+	if (!pair) return { text: content.trim(), reasoning: '' };
+
+	const bodyStart = pair.open.length;
+	const closeIndex = trimmed.indexOf(pair.close, bodyStart);
+
+	// Cut off mid-thought: keep it as reasoning rather than leak it as the reply.
+	if (closeIndex === -1) {
+		return { text: '', reasoning: trimmed.slice(bodyStart).trim() };
+	}
+
+	return {
+		text: trimmed.slice(closeIndex + pair.close.length).trim(),
+		reasoning: trimmed.slice(bodyStart, closeIndex).trim(),
+	};
+};
+
+export default extractReasoning;