feat: close #826 #827 #828 #829 — cross-chain identity, collateral baskets, boost curves, amortization schedules

[Spycall]

Summary

Closes #826,
Closes #827,
Closes #828,
Closes #829

Changes

Issue #826 — Gate property issuance on cross-chain identity verification

• Added identity_registry storage field + set_identity_registry setter to property-management
• Added verify_onboarding_cross_chain — XCM-style mock calling ComplianceChecker trait
• Added register_property message gated on cross-chain attestation
• Test: register_property_fails_without_identity_registry covers unattested path

Issue #827 — Multi-token collateral baskets

• Added collateral_basket: Vec<(TokenId, u128)> field to LoanListing
• Updated create_loan_listing to accept collateral_basket parameter
• Tests: create_loan_listing_with_collateral_basket, create_loan_listing_with_empty_basket

Issue #828 — Yield boosters for long-term staking

• Added BoostCurve enum (Linear | Concave | Convex) with apply() method
• Added sqrt_u128 helper for concave curve
• Added multiplier_with_curve() + ratio() methods on LockPeriod
• boost_curve storage field + governance parameter (ParamKind::BoostCurve)
• Integrated into calculate_rewards and calculate_projected_rewards
• 13 unit tests covering all curve shapes and edge cases

Issue #829 — Variable amortization schedules

• Added Schedule enum (Bullet | Annuity | Linear | Custom) with installment() computation
• Added schedule_type: Schedule field to PaymentSchedule
• Added create_payment_schedule message + get_payment_schedule_by_loan query
• Tests: Bullet, Annuity, Linear, Custom schedule types + unauthorized access check

Files Changed

• contracts/lending/src/lib.rs — Schedule enum, PaymentSchedule integration, multi-token collateral
• contracts/lending/src/test.rs — 8 new ink! tests for Support multi-token collateral baskets in loan marketplace #827 and Variable amortization schedules in lending #829
• contracts/property-management/src/lib.rs — Identity registry, cross-chain verification, property registration gate
• contracts/staking/src/lib.rs — BoostCurve storage, governance, reward calc integration
• contracts/staking/src/types.rs — BoostCurve enum, multiplier_with_curve, ratio, 13 unit tests

Note: Cargo was unavailable in the dev environment — please run cargo check --workspace && cargo test --workspace before merging to confirm compilation and test pass.

[drips-wave]

Hey @Spycall! 👋 It looks like this PR isn't linked to any issue.

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Issue	Title
#827	Support multi-token collateral baskets in loan marketplace	Link to this issue
#826	Gate property issuance on cross-chain identity verification	Link to this issue
#828	Add yield boosters for long-term staking	Link to this issue
#829	Variable amortization schedules in lending	Link to this issue

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[nanaf6203-bit]

LGTM