fix: Added RUNVM return stack length restriction

[Shvandre]

Closes #102

[Copilot]

Pull Request Overview

This PR fixes a security vulnerability in the calculateJettonWallet function by adding return stack length restriction to the RUNVM operation. The change addresses stack poisoning attacks by limiting the number of return values and using proper RUNVM mode flags.

• Updated RUNVM call to use mode 277 (combination of flags +1, +4, +16, +256) instead of mode 53
• Added stack length restriction by expecting only 1 return value using flag +256
• Updated stack cleanup from 3 BLKDROP to 2 BLKDROP to match the new return pattern

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[Shvandre]

Merged #103, that was the reason of failing CI here

[skywardboundd]

solid work