🛠️ [TASK] : Add stub endpoints to support `norns`

[apskhem]

Summary

Stub and Add Endpoints to Catalyst-Voices for Norns App Compatibility (No Implementation Needed)

Description

• The endpoints should be fully stubbed with proper return types that match the original system.
• They do not need actual implementations at this time, just enough functionality for the Norns app to work with them.
• Analyze what these endpoints do in the original system and how the norns app interacts with the responses.
• Ensure they work as needed for norns, but do not expose them in the public API. These endpoints will be deprecated and hidden before we go live.

Reference this repository for context: Norns Repository Search.

As listed in this epic.
This ticket aims to implement only 6 of them.

• GET /api/v0/settings - App.getAppSettings()
• GET /api/v0/fund/ - Fund.show()
• GET /api/v0/proposals - Proposal.index()
• POST /api/v0/proposals - Proposal.get_proposal_by_idx(votingHistoryList)
• GET /api//v0/proposals/${id} - Proposal.show(id)
• GET /api/v0/reviews/${proposalId} - Proposal.review(proposalId)