[emdevelopa]

Summary of Changes

This pull request resolves four issues across the Parashield contracts:

1. RiskPool Premium Split Validation ([bug] RiskPool does not validate premium split sum equals 10000 bps #756):

   • Enforce that the sum of all premium split components (lp_bps + treas_bps + backstop_bps) strictly equals 10,000 bps (100%) in execute_parameter_change.
   • Prevent under/over-allocation of pool yields.

2. PolicyEngine Product Description Validation ([bug] PolicyEngine does not validate product description is not empty #755):

   • Validate that params.name is non-empty and has a valid minimum character length in create_product.
   • Added EmptyDescription and InvalidDescription error variants to prevent uninformative products.

3. ClaimsProcessor Claim Reference Uniqueness ([bug] ClaimsProcessor does not validate claim reference number is unique #754):

   • Added submit_claim_with_ref entrypoint and StorageKey::ClaimReference(Symbol) tracking.
   • Enforce unique claim reference numbers, rejecting duplicates with Error::DuplicateClaimReference.

4. RiskPool Zero Address Admin Validation ([security] RiskPool does not validate admin address is not the zero address #753):

   • Enforce require_not_zero_address on admin address during pool initialisation (initialize), admin rotation proposal (propose_new_admin), and acceptance (accept_admin).
   • Prevents permanently locking contract administration to the zero address.

Closes #756
Closes #755
Closes #754
Closes #753