feat: add get_proposals to query governance proposals

[mkoura]

Introduce the get_proposals method in QueryGroup to retrieve governance proposals eligible for ratification. The method allows querying all proposals or filtering by specific governance action transaction ID and index.

[Copilot]

Pull Request Overview

Adds a new get_proposals method to the QueryGroup class for retrieving governance proposals eligible for ratification. The method supports querying all proposals or filtering by specific governance action transaction ID and index.

Key Changes

• Implemented get_proposals method with optional filtering parameters
• Added validation to ensure action_txid and action_ix are provided together
• Integrated with CLI query commands for proposal retrieval

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