feat: support multiple proof systems in STM

[jpraynaud]

Content

This PR includes support for multiple proof systems in the STM library:

• Adds AggregateSignatureType enum with initial support for Concatenation proof system
• Refactors AggregateSignature from struct to enum to support multiple proof system implementations (a new proof is now implemented in a dedicated sub-module of the proof sub-module)
• Update of aggregator, e2e tests, infrastructure and CI to include the configuration of the aggregate signature type

Pre-submit checklist

• Branch
  • Tests are provided (if possible)
  • Crates versions are updated (if relevant)
  • CHANGELOG file is updated (if relevant)
  • Commit sequence broadly makes sense
  • Key commits have useful messages
• PR
  • All check jobs of the CI have succeeded
  • Self-reviewed the diff
  • Useful pull request description
  • Reviewer requested
• Documentation
  • No new TODOs introduced

Issue(s)

Closes #2680

[github-actions]

Test Results

    4 files  ±0    164 suites  ±0   23m 39s ⏱️ -21s
2 195 tests +2  2 195 ✅ +2  0 💤 ±0  0 ❌ ±0 
6 760 runs  +7  6 760 ✅ +7  0 💤 ±0  0 ❌ ±0 

Results for commit d4b30d4. ± Comparison against base commit 098106d.

♻️ This comment has been updated with latest results.

[Copilot]

Pull Request Overview

This PR introduces support for multiple proof systems in the STM (Stake-based Threshold Multisignature) implementation by adding an aggregate signature type parameter. The main change refactors the existing concatenation proof system into a modular structure that can support future proof systems.

• Adds AggregateSignatureType enum with initial support for Concatenation proof system
• Refactors AggregateSignature from struct to enum to support multiple proof system implementations
• Updates configuration, API, and infrastructure to include aggregate signature type parameter

Reviewed Changes

Copilot reviewed 45 out of 46 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
openapi.yaml	Adds aggregate_signature_type field to API specifications and examples
mithril-stm/src/aggregate_signature/signature.rs	Refactors AggregateSignature from struct to enum with proof system abstraction
mithril-stm/src/aggregate_signature/proof/	Creates new modular proof system structure with concatenation implementation
mithril-aggregator/src/configuration.rs	Adds aggregate signature type configuration parameter
mithril-common/src/messages/aggregator_features.rs	Updates aggregator capabilities to include signature type
mithril-test-lab/	Updates test infrastructure to support aggregate signature type parameter

Comments suppressed due to low confidence (2)

mithril-stm/src/aggregate_signature/signature.rs:1

• Use proper Rust formatting with a space after 'else'. Should be } else { instead of }else{.

use std::collections::HashMap;

mithril-stm/src/aggregate_signature/signature.rs:1

• Use proper Rust formatting with a space after 'else'. Should be } else { instead of }else{.

use std::collections::HashMap;

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[turmelclem]

LGTM 👍

[curiecrypt]

Left some minor comments, questions 😊

[curiecrypt]

LGTM 🚀