Quadratic voting example showcasing libraries

[mohammadfawaz]

Summary

quadratic_vote is a governance example that demonstrates Leo library packages and library submodules.

Two reusable libraries handle all the math:

Package	Kind	What it provides
sqrt_math	library	isqrt — integer square root via Newton's method
vote_math	library	QV weights, credit costs, voter profiles (depends on sqrt_math)
governance.aleo	program	Private vote records, proposal outcome checks

Under Quadratic Voting (QV), a participant's vote weight equals ⌊√(token_balance)⌋ and casting k votes costs k² credits. This makes influence grow with the square root of wealth rather than linearly — fairer to smaller holders.

Noteworthy Features

• Library packages — sqrt_math and vote_math have no .aleo program name, are never deployed on their own, and only take effect when included by a program package.
• Library submodules — each extra .leo file under src/ becomes a named module; no declaration needed.
• Cross-submodule calls within a library — vote_math::cost::build_profile calls vote_math::weight::compute; sqrt_math::checks::is_perfect_square calls sqrt_math::newton::isqrt.
• Cross-library submodule calls — vote_math::weight::compute reaches directly into sqrt_math::newton::isqrt, demonstrating the full dependency chain (governance → vote_math → sqrt_math).
• Top-level library constants — sqrt_math::ISQRT_MAX, vote_math::MAX_WEIGHT, and vote_math::MIN_BALANCE are defined in lib.leo and referenced by name from within submodules.
• Library struct export — vote_math::cost::VoterProfile is defined in a submodule and used as a variable type inside governance.aleo.
• Private vote receipt — the Vote record is private; the token balance that drove the weight computation is never revealed on-chain.

Test plan

• cd quadratic_vote/sqrt_math && leo build
• cd quadratic_vote/vote_math && leo build
• cd quadratic_vote/governance && leo build
• cd quadratic_vote/governance && leo test → 18/18 pass
• cd quadratic_vote && bash run.sh → all steps produce expected output