Add supply-cap zero-vs-max-i128 differential test locking boundary semantics

[thlpkee20-wq]

Description

supply_cap == 0 means disabled, supply_cap == i128::MAX means unbounded-but-enabled. Lock these semantics with a differential test asserting distinct code paths and event streams.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: src/test_compute_share_invariants.rs
• Test must run both configurations on identical inputs

Suggested execution

• Fork the repo and create a branch
• git checkout -b test/supply-cap-boundaries
• Implement changes
  • Two fixtures: cap=0 and cap=i128::MAX
  • Run identical issuance sequences
  • Assert expected event and state differences
• Validate security and correctness assumptions

Test and commit

• Run tests
  • cargo test --all
• Cover edge cases
  • Total issuance near i128::MAX
• Include test output and security notes

Example commit message

test: differential test for supply-cap boundaries

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours