feat(files): introduce upload_file tool for staging files and enhance save_file documentation

internal/ai/compat/client.go

@@ -224,7 +224,7 @@ func (c *Client) ExtractMetadata(ctx context.Context, input string) (thoughttype
 		attrs := []any{
 			slog.String("provider", c.name),
 			slog.String("model", model),
-			slog.Duration("duration", time.Since(start)),
+			slog.String("duration", formatLogDuration(time.Since(start))),
 		}
 		if err != nil {
 			attrs = append(attrs, slog.String("error", err.Error()))
@@ -298,6 +298,18 @@ func (c *Client) ExtractMetadata(ctx context.Context, input string) (thoughttype
 	return heuristic, nil
 }
 
+func formatLogDuration(d time.Duration) string {
+	if d < 0 {
+		d = -d
+	}
+
+	totalMilliseconds := d.Milliseconds()
+	minutes := totalMilliseconds / 60000
+	seconds := (totalMilliseconds / 1000) % 60
+	milliseconds := totalMilliseconds % 1000
+	return fmt.Sprintf("%02d:%02d:%03d", minutes, seconds, milliseconds)
+}
+
 func (c *Client) extractMetadataWithModel(ctx context.Context, input, model string) (thoughttypes.ThoughtMetadata, error) {
 	if c.shouldBypassModel(model) {
 		return thoughttypes.ThoughtMetadata{}, fmt.Errorf("%s metadata: model %q temporarily bypassed after repeated empty responses", c.name, model)