Param management for all missing elements. No CLI commands yet

[mkysel]

Add parameter management for all missing app-chain and settlement-chain elements by introducing admin getters/setters for group and identity payload sizes and settlement parameters with uint16, uint32, uint64, and uint96 support in ParameterAdmin, with no CLI commands

This change adds missing parameter-management surfaces across the app-chain and settlement-chain admins and implements canonical encoding/decoding for multiple integer widths in the parameter admin.

• Update appchainAdmin.go to add IAppChainAdmin methods for Get/SetGroupMessageMaxPayloadSize, Get/SetGroupMessageMinPayloadSize, Get/SetIdentityUpdateMaxPayloadSize, and Get/SetIdentityUpdateMinPayloadSize, persisting parameters and executing on-chain broadcaster updates with event parsing.
• Update parameterAdmin.go to implement canonical pack/decode for uint8/uint16/uint32/uint64/uint96, add GetParameterUint16, GetParameterUint32, GetParameterUint96, and SetUint16Parameter, SetUint32Parameter, SetUint96Parameter, and refactor logging and batch packing to use the new helpers.
• Update settlementChainAdmin.go to expand ISettlementChainAdmin with getters/setters for distribution manager protocol fees recipient, node registry admin, payer registry minimum deposit (uint96), withdraw lock period (uint32), payer report manager protocol fee rate (uint16), and rate registry migrator, executing relevant on-chain updates with event parsing where applicable.
• Add tests in appchainAdmin_test.go, parameterAdmin_test.go, and settlementchainAdmin_test.go covering read/write flows, idempotency, and encoding boundaries.

📍Where to Start

Start with the packing/decoding helpers and new getters/setters in parameterAdmin.go, then review how they are used in settlementChainAdmin.go and appchainAdmin.go.

Changes since #1092 opened

• Modified logging format for minimumDeposit field in blockchain.settlementChainAdmin.SetPayerRegistryMinimumDeposit method [8c1f294]

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Macroscope summarized 8c1f294.

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