fix(insurance): fix duplicate function and u128/u32 type mismatch in premium_engine.rs

[nanaf6203-bit]

Problem

contracts/insurance/src/premium_engine.rs had multiple compilation errors:

1. Duplicate function name — calculate_adjustment_amount was defined twice with different arities. Rust does not support function overloading.

2. u128 / u32 division — BASIS_POINTS_DENOMINATOR was declared as u32 but used as a divisor for u128 expressions throughout the file. Rust requires matching types for division.

3. Ambiguous integer type — base_deductible_rate and risk_adjustment were untyped integer literals, causing E0689 when calling .saturating_add().

4. Wrong argument count — call sites passed 4 or 6 args to calculate_adjustment_amount which expected 5.

5. Option<ActuarialModel> vs Option<&ActuarialModel> — calculate_dynamic_premium expects a reference but was passed an owned Option.

Fix

• Renamed the two overloaded functions to calculate_coverage_adjustment_amount, calculate_pool_adjustment_amount, calculate_time_adjustment_amount.
• Changed BASIS_POINTS_DENOMINATOR from u32 to u128.
• Added explicit u128 type annotations to ambiguous literals.
• Updated all call sites.
• Added .as_ref() at the call site in lib.rs.

Affected files

• contracts/insurance/src/premium_engine.rs
• contracts/insurance/src/lib.rs

[Alqku]

@Alqku has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

can I work on this please

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[drips-wave]

Congratulations, @Alqku! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

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