feat: add app ping url

[manuel-rw]

Homarr

Thank you for your contribution. Please ensure that your pull request meets the following pull request:

• Builds without warnings or errors (pnpm build, autofix with pnpm format:fix)
• Pull request targets dev branch
• Commits follow the conventional commits guideline
• No shorthand variable names are used (eg. x, y, i or any abbrevation)

[deepsource-io]

Here's the code health analysis summary for commits 9d54e93..f37e0b2. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
JavaScript	✅ Success		View Check ↗

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[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	21.5%	8845 / 41137
🔵	Statements	21.5%	8845 / 41137
🔵	Functions	26.78%	346 / 1292
🔵	Branches	62.03%	1013 / 1633

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/api/src/router/app.ts	75.6%	81.25%	100%	75.6%	22-35, 51-55, 73-83, 112-114, 139-147
packages/db/schema/mysql.ts	100%	100%	100%	100%
packages/db/schema/sqlite.ts	100%	100%	100%	100%
packages/forms-collection/src/new-app/_form.tsx	0%	0%	0%	0%	1-115
packages/modals-collection/src/docker/add-docker-app-to-homarr.tsx	0%	0%	0%	0%	1-92
packages/old-import/src/import-apps.ts	0%	0%	0%	0%	1-160
packages/old-import/src/mappers/map-app.ts	9.09%	100%	0%	9.09%	8-16, 19-29
packages/validation/src/app.ts	100%	71.42%	100%	100%
packages/widgets/src/app/component.tsx	0%	0%	0%	0%	1-126
packages/widgets/src/bookmarks/add-button.tsx	30%	100%	0%	30%	22-30

Generated in workflow #5221 for commit f37e0b2 by the Vitest Coverage Report Action

[Meierschlumpf]

If you agree with my points and are able to fix them until todays release, you can merge this PR if you want. If you don't agree then we can discuss further after it and release it next week