[Contract] Build Insurance Policy Lifecycle

[yusuftomilola]

On-chain insurance policy management for tokenized assets. Policies track coverage, premiums, and validity periods.

Requirements

InsurancePolicy struct: policy_id: BytesN<32>, holder: Address, insurer: Address, asset_id: BytesN<32>, policy_type: PolicyType (enum: Liability, Property, Comprehensive, Custom), coverage_amount: i128, deductible: i128, premium: i128, start_date: u64, end_date: u64, status: PolicyStatus (Active, Suspended, Expired, Cancelled), auto_renew: bool, last_payment: u64

Functions:

• create_insurance_policy(...) — Validates dates, stores policy, indexes by asset ID
• cancel_insurance_policy(env, policy_id, caller) — caller must be holder or insurer
• suspend_insurance_policy(env, policy_id, insurer) — insurer only
• expire_insurance_policy(env, policy_id) — permissionless; validates end_date < current timestamp
• renew_insurance_policy(env, policy_id, new_end_date, insurer) — insurer only
• get_insurance_policy, get_asset_insurance_policies

Acceptance Criteria

• Policy status transitions are valid (Active → Cancelled, Active → Suspended, etc.)
• expire_policy fails if end_date has not yet passed
• Asset index maintains all policy IDs for that asset