chore: Release 3.5.4

[TheRealAgentK]

chore: Release 3.5.4

Patch release that ships the toJson() fix from #315 (closes #313), the test-coverage expansion from #314, and the four Dependabot dependency bumps merged this week.

No production behaviour change on the wire. The SDK already serialised correctly via jsonEncode(); #315 just fixes the in-memory shape returned by toJson() to match its declared Map<String, dynamic> signature.

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Description 📝

Purpose
Cut the 3.5.4 release.

Approach
Follow RELEASING.md:

1. Bump version in pubspec.yaml and kVersion in lib/src/services/settings.dart
2. Run flutter pub get so example/pubspec.lock picks up 3.5.4
3. Prepend the new ## 3.5.4 section to CHANGELOG.md
4. Verify with dart format, flutter analyze, flutter test, flutter pub publish --dry-run

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Why patch?

Change	Wire format	Public API signature	Verdict
#315 — innerError fix	unchanged	unchanged	Bug fix
#314 — test additions	n/a	n/a	No version impact
#309–#312 — Dependabot	unchanged	unchanged	Transitive bumps within existing ranges

No incompatible changes, no new functionality → patch.

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Type of change

• Bug fix (non-breaking change which fixes an issue)

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Updates

• 👉 pubspec.yaml — version: 3.5.3 → 3.5.4
• 👉 lib/src/services/settings.dart — kVersion = '3.5.3' → '3.5.4' (sent in every payload's details.client.version)
• 👉 example/pubspec.lock — refreshed by flutter pub get so the example app references the local 3.5.4 path
• 👉 CHANGELOG.md — new ## 3.5.4 entry

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CHANGELOG entry

## 3.5.4

- fix: emit nested toJson() for json_serializable models (#313) (#315) (2026-05-04)
- test: expand unit test coverage for public API and serialisation (#314) (2026-05-04)
- chore(deps): bump json_serializable from 6.13.1 to 6.13.2 (#309) (2026-05-04)
- chore(deps): bump build_runner from 2.13.1 to 2.15.0 (#310) (2026-05-04)
- chore(deps): bump connectivity_plus from 7.1.0 to 7.1.1 (#311) (2026-05-04)
- chore(deps): bump package_info_plus from 9.0.0 to 9.0.1 (#312) (2026-05-04)

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Test plan 🧪

flutter pub get
dart format --set-exit-if-changed .
flutter analyze
flutter test
flutter pub publish --dry-run

Verified locally on release/3.5.4:

Check	Result
dart format --set-exit-if-changed .	✅ clean (38 files, 0 changed)
flutter analyze	✅ No issues found!
flutter test	✅ 36 / 36 passed
flutter pub publish --dry-run	✅ clean once the release commit lands

CI also covers the example builds for Android, iOS, macOS, Linux, Web (JS), Web (WASM) — none affected because there are no production code changes in this PR (just version metadata + CHANGELOG).

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Post-merge checklist (for whoever publishes)

Per RELEASING.md:

1. flutter pub publish (needs Raygun pub.dev credentials)
2. Squash & merge this PR into develop
3. Create a GitHub Release for tag 3.5.4 (auto-generated release notes are fine)
4. Open a chore: merge to master PR from develop → master and use a regular merge (not squash)

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Author to check 👓

• Project and all contained modules builds successfully
• Self-/dev-tested
• Unit/UI/Automation/Integration tests provided where applicable
• Code is written to standards
• Appropriate documentation written (code comments, internal docs)

Reviewer to check ✔️

• Project and all contained modules builds successfully
• Change has been dev-/reviewer-tested, where possible
• Unit/UI/Automation/Integration tests provided where applicable
• Code is written to standards
• Appropriate documentation written (code comments, internal docs)