feat(prompts): add new templates for memory migration and weekly review

internal/ai/compat/client.go

@@ -171,6 +171,7 @@ func (c *Client) ExtractMetadata(ctx context.Context, input string) (thoughttype
 
 	metadataText := strings.TrimSpace(resp.Choices[0].Message.Content)
 	metadataText = stripCodeFence(metadataText)
+	metadataText = extractJSONObject(metadataText)
 
 	var metadata thoughttypes.ThoughtMetadata
 	if err := json.Unmarshal([]byte(metadataText), &metadata); err != nil {
@@ -286,6 +287,17 @@ func (c *Client) doJSON(ctx context.Context, path string, requestBody any, dest
 	return lastErr
 }
 
+// extractJSONObject finds the first complete {...} block in s.
+// It handles models that prepend prose to a JSON response despite json_object mode.
+func extractJSONObject(s string) string {
+	start := strings.Index(s, "{")
+	end := strings.LastIndex(s, "}")
+	if start == -1 || end == -1 || end <= start {
+		return s
+	}
+	return s[start : end+1]
+}
+
 func stripCodeFence(value string) string {
 	value = strings.TrimSpace(value)
 	if !strings.HasPrefix(value, "```") {