Support Codex 0.134 approvals

Use available approval decisions from the app-server schema, preserve structured policy decisions in callbacks, and keep approval rendering aligned with normal tool-call output.

Also simplify thread commands, clear stale active turns more carefully, and update command/help docs.

internal/telegram/api.go

@@ -50,6 +50,11 @@ func (c *Client) redact(text string) string {
 	return strings.ReplaceAll(text, c.token, "<telegram-token>")
 }
 
+func (c *Client) SetMyCommands(ctx context.Context, commands []BotCommand) error {
+	var ok bool
+	return c.postJSON(ctx, "setMyCommands", map[string]any{"commands": commands}, &ok)
+}
+
 func (c *Client) GetUpdates(ctx context.Context, offset int, timeoutSeconds int) ([]Update, error) {
 	params := map[string]any{
 		"offset":          offset,