Replace map-based Multi signature with slice-based version for better performance

[meling]

(The code for this has been sitting on my local working copy for so long that I decided to clean it up and get it integrated...)

This PR replaces the map[hotstuff.ID]T with []T in the Multi type:

  type Multi[T Signature] []T

The rationale for this change is that map-based data structures are often much slower for small to medium-sized sets/lists. It is often faster to iterate over N entries than to do a map lookup. See the benchmark results below.

This PR also makes the following changes/updates:

• Add comprehensive tests for the multi-signature functionality
• Replace Restore with NewMulti constructor
• Add NewMultiSorted constructor to ensure sorted signatures (not used now, but it is available should the need arise)
• Updated ECDSA and EDDSA implementations to use slice-based Multi
• Updated the kauri tests to use the slice-based Multi

This change reduces memory overhead and improves iteration performance by using a slice instead of a map for storing partial signatures.

goos: darwin
goarch: arm64
pkg: github.com/relab/hotstuff/security/crypto
cpu: Apple M2 Max
                  │ map-multisig.txt │         slice-multisig.txt          │
                  │      sec/op      │   sec/op     vs base                │
ForEach/n=10-12          92.62n ± 4%   19.54n ± 0%  -78.90% (p=0.000 n=20)
ForEach/n=100-12         637.8n ± 2%   212.9n ± 1%  -66.61% (p=0.000 n=20)
ForEach/n=1000-12        7.552µ ± 1%   2.026µ ± 0%  -73.16% (p=0.000 n=20)
ToBytes/n=10-12          1.699µ ± 0%   1.402µ ± 0%  -17.51% (p=0.000 n=20)
ToBytes/n=100-12         18.11µ ± 0%   14.18µ ± 1%  -21.71% (p=0.000 n=20)
ToBytes/n=1000-12        220.4µ ± 1%   157.4µ ± 1%  -28.61% (p=0.000 n=20)
geomean                  3.803µ        1.725µ       -54.64%

                  │ map-multisig.txt │          slice-multisig.txt           │
                  │       B/op       │     B/op      vs base                 │
ForEach/n=10-12         0.000 ± 0%       0.000 ± 0%       ~ (p=1.000 n=20) ¹
ForEach/n=100-12        0.000 ± 0%       0.000 ± 0%       ~ (p=1.000 n=20) ¹
ForEach/n=1000-12       0.000 ± 0%       0.000 ± 0%       ~ (p=1.000 n=20) ¹
ToBytes/n=10-12       3.422Ki ± 0%     3.375Ki ± 0%  -1.37% (p=0.000 n=20)
ToBytes/n=100-12      40.22Ki ± 0%     39.81Ki ± 0%  -1.01% (p=0.000 n=20)
ToBytes/n=1000-12     438.9Ki ± 0%     434.9Ki ± 0%  -0.91% (p=0.000 n=20)
geomean                            ²                 -0.55%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                  │ map-multisig.txt │          slice-multisig.txt          │
                  │    allocs/op     │  allocs/op   vs base                 │
ForEach/n=10-12         0.000 ± 0%      0.000 ± 0%       ~ (p=1.000 n=20) ¹
ForEach/n=100-12        0.000 ± 0%      0.000 ± 0%       ~ (p=1.000 n=20) ¹
ForEach/n=1000-12       0.000 ± 0%      0.000 ± 0%       ~ (p=1.000 n=20) ¹
ToBytes/n=10-12         46.00 ± 0%      45.00 ± 0%  -2.17% (p=0.000 n=20)
ToBytes/n=100-12        412.0 ± 0%      411.0 ± 0%  -0.24% (p=0.000 n=20)
ToBytes/n=1000-12      4.020k ± 0%     4.019k ± 0%  -0.02% (p=0.000 n=20)
geomean                            ²                -0.41%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

[Copilot]

Pull Request Overview

This PR replaces the map-based Multi signature type with a slice-based version to improve performance for small to medium-sized signature sets, showing significant performance improvements (54-79% faster) based on benchmark results.

• Replaced map[hotstuff.ID]T with []T in the Multi type definition
• Added comprehensive test coverage for multi-signature functionality
• Updated ECDSA and EDDSA implementations to use the new slice-based approach

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
security/crypto/multisignature.go	Core change replacing map with slice and updating all Multi methods
security/crypto/multisignature_test.go	New comprehensive test file for multi-signature functionality
security/crypto/ecdsa.go	Updated ECDSA implementation to use slice-based Multi
security/crypto/eddsa.go	Updated EDDSA implementation to use slice-based Multi
internal/proto/hotstuffpb/convert.go	Updated to use NewMulti instead of deprecated Restore
internal/test/name.go	Enhanced Name function with better API and field-value pair handling
protocol/comm/kauri/kauri_test.go	Updated tests to use new Multi signature creation pattern
twins/network_test.go	Minor test name generation update
protocol/synchronizer/timeout_collector_test.go	Minor test name generation update
internal/orchestration/orchestration_test.go	Minor test name generation update

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