feat(api): add items and groups api endpoints

[Meierschlumpf]

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)
• Documentation is up to date. Create a pull request here.

Closes #3705
Related #3473

[deepsource-io]

Here's the code health analysis summary for commits 1d485cf..5332f0d. 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	25.45%	14851 / 58352
🔵	Statements	25.45%	14851 / 58352
🔵	Functions	37.83%	687 / 1816
🔵	Branches	72.15%	1653 / 2291

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/api/src/router/board.ts	60.35%	80.85%	82.35%	60.35%	67-75, 78-85, 91-116, 192-261, 311-522, 539-543, 556-558, 561-563, 571, 761-957, 979-999, 1115-1130, 1218, 1237, 1246-1259, 1264-1265, 1285-1300, 1305-1306, 1325-1327, 1353-1355, 1446-1447, 1471-1472, 1576-1580, 1637-1638, 1646-1647
packages/api/src/router/group.ts	77.25%	94.44%	100%	77.25%	40-60, 188-210, 221-228, 234-250, 298-306, 312-329, 398-402, 452-456
packages/api/src/router/board/items/item-router.ts	66.28%	100%	100%	66.28%	76-96, 138-180, 187
packages/db/validationSchemas.ts	100%	100%	100%	100%
packages/widgets/src/definition.ts	100%	100%	100%	100%
packages/widgets/src/index.tsx	70.83%	100%	0%	70.83%	86-102, 117-130
packages/widgets/src/options.ts	96.39%	75%	100%	96.39%	112-115
packages/widgets/src/bookmarks/index.tsx	58.92%	100%	20%	58.92%	30-48, 52-59

Generated in workflow #8093 for commit 5332f0d by the Vitest Coverage Report Action