Composio connection under non-default user_id breaks account checks

A Composio connected account (ca_...) created from the dashboard or CLI is often owned by a custom user_id (e.g. 'voiceos-tiktok'), not 'default'. Integrations that filter GET /connected_accounts by user_ids=default then report 'not connected' even though the connection is ACTIVE. Fix: when the configured user id is empty or 'default', list by connected_account_ids only and adopt the account's user_id for /tools/execute; keep strict matching when a user id is set explicitly. Also: Composio's /files/upload/request currently returns Cloudflare R2 presigned URLs (temp.<hash>.r2.cloudflarestorage.com), not storage.composio.dev, so allowlist that host.