helius-phantom: USDC Sender example misses mandatory Jito tip + compute budget instructions #63

Summary

The payWithUSDC example in skills/helius-phantom/references/payments.md submits to Helius Sender (https://sender.helius-rpc.com/fast) but does not include mandatory Sender transaction instructions.

Why this is a problem

skills/helius-phantom/references/helius-sender.md states that every Sender transaction must include:

1. skipPreflight: true (already present)
2. A Jito tip transfer instruction (missing)
3. Compute budget instructions (setComputeUnitLimit + setComputeUnitPrice) (missing)

Without these, generated USDC payment code can be rejected or fail to benefit from Sender routing.

Affected location

• skills/helius-phantom/references/payments.md (USDC section, payWithUSDC)

Suggested fix

Align payWithUSDC with the SOL and SPL Sender patterns by adding:

• getSetComputeUnitLimitInstruction
• getSetComputeUnitPriceInstruction (using dynamic getPriorityFeeEstimate)
• Jito tip transfer to a random tip account (0.0002 SOL)

I opened a PR with this exact fix.