Truncate long text in the middle with an ellipsis

Truncate long text in the middle with an ellipsis. Call when you keep start+end context inside UI/log width limits. Returns truncated text and truncated flag for $0.001 USDC via x402 on Base. No network, no keys, no retention; first-party local JSON only. Results are advisory; the caller owns budgets, auth, and production controls.