[client] Add theme preference store coverage

[TechHutTV]

Describe your changes

The preferences store now has focused regression coverage for theme defaults, valid and invalid persisted values, persistence across reloads, subscriber broadcasts, and idempotent updates. These tests protect the existing theme preference behavior without changing production code.

Relates to #7344

Issue ticket number and link

Not applicable: test-only coverage; no behavior changes.

Stack

Checklist

• Is it a bug fix
• Is a typo/documentation fix
• Is it a feature enhancement
• It is a refactor
• Created tests that fail without the change (if possible)
• I ran and tested this change locally — I did not rely on CI to find out whether it works
• This PR has a single purpose (not a fix + refactor + feature in one)
• This change is a trivial fix, OR it links an issue the NetBird team agreed on beforehand. Changes to the public API, gRPC protocols, functionality behavior, CLI / service flags, or new features always need that agreement first. See CONTRIBUTING.md.

By submitting this pull request, you confirm that you have read and agree to the terms of the Contributor License Agreement.

Documentation

Select exactly one:

• I added/updated documentation for this change
• Documentation is not needed for this change (explain why)

This PR adds tests only and does not change user-facing behavior or documentation.

Docs PR URL (required if "docs added" is checked)

Paste the PR link from https://github.com/netbirdio/docs here:

https://github.com/netbirdio/docs/pull/__

Summary by CodeRabbit

• Tests
  • Expanded coverage for theme preference behavior, including system defaults, light and dark themes, and settings loaded from existing files.
  • Added validation for unsupported or unknown theme values, ensuring they fall back safely or are rejected as appropriate.
  • Verified that theme changes persist across reloads, notify the application once, and avoid duplicate notifications when unchanged.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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Review profile: CHILL

Plan: Advanced

Run ID: 2cc6e63d-5809-46d7-a338-a5f61cb09b08

📥 Commits

Reviewing files that changed from the base of the PR and between 08699a9 and c403c7e.

📒 Files selected for processing (1)

• client/ui/preferences/store_test.go

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📝 Walkthrough

Walkthrough

The preferences store tests now cover theme defaults, stored values, updates, persistence, broadcasts, idempotency, and rejection of unsupported values.

Changes

Preference theme behavior

Layer / File(s)	Summary
Theme loading and defaults client/ui/preferences/store_test.go	Tests verify ThemeSystem defaults for missing and corrupt files, legacy files without a theme, unknown values, and valid stored themes.
Theme mutation and persistence client/ui/preferences/store_test.go	Tests verify supported theme updates, persistence across reloads, one change broadcast, idempotent updates, and ErrUnsupportedTheme handling.

Suggested reviewers: mlsmaycon

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Other

Merge Risk: ⚪ Minimal · up to c403c

The added tests cover theme defaults, persistence, notifications, and validation without changing production behavior. The change is ready to merge.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the addition of theme preference store test coverage.
Description check	✅ Passed	The description follows the repository template, explains the test-only scope, identifies the related pull request, records the relevant checklist items, and explains why documentation is not needed.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/preferences-theme-coverage

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cubic-dev-ai]

No issues found across 1 file

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[github-actions]

Release artifacts

Built for PR head c403c7e in workflow run #19010.

Artifact	Link
All release artifacts	Download
Linux packages	Download
Windows packages	Download
macOS packages	Download
UI artifacts	Download
UI GTK3 artifacts	Download
UI macOS artifacts	Download

GHCR images (amd64)

• ghcr.io/netbirdio/management:pr-7555
• ghcr.io/netbirdio/netbird-server:pr-7555
• ghcr.io/netbirdio/netbird:pr-7555
• ghcr.io/netbirdio/netbird:pr-7555-rootless
• ghcr.io/netbirdio/netbird:pr-7555-rootless-ubi
• ghcr.io/netbirdio/relay:pr-7555
• ghcr.io/netbirdio/reverse-proxy:pr-7555
• ghcr.io/netbirdio/signal:pr-7555
• ghcr.io/netbirdio/upload:pr-7555

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