fix: flakiness in DMQ integration tests in CI

[jpraynaud]

Content

This PR includes a fix for the DMQ integration tests flakiness which was due to non deterministic timestamp provider when signing DMQ messages with KES keys.

Pre-submit checklist

• Branch
  • Tests are provided (if possible)
  • Crates versions are 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

Issue(s)

Closes #2728

[github-actions]

Test Results

    4 files  ±0    164 suites  ±0   23m 50s ⏱️ -11s
2 195 tests ±0  2 195 ✅ ±0  0 💤 ±0  0 ❌ ±0 
6 760 runs  ±0  6 760 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit a26d829. ± Comparison against base commit d7ce977.

♻️ This comment has been updated with latest results.

[Copilot]

Pull Request Overview

This PR fixes flakiness in DMQ (Decentralized Message Queue) integration tests by implementing deterministic timestamp handling for KES key message signing.

• Introduces a FakeUnixTimestampProvider test double for deterministic timestamp generation
• Updates DMQ message builders in tests to use the fake timestamp provider
• Version bump from 0.1.11 to 0.1.12

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/mithril-dmq/src/test/double/timestamp.rs	New fake timestamp provider implementation for testing
internal/mithril-dmq/src/test/double/mod.rs	Module exports for the new timestamp test double
internal/mithril-dmq/src/test/fake_message.rs	Updated to use deterministic timestamp provider
internal/mithril-dmq/tests/publisher_client_server.rs	Integration test updated to use fake timestamp provider
internal/mithril-dmq/Cargo.toml	Version bump to 0.1.12

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Alenar]

LGTM

[turmelclem]

LGTM 👍