feat(widgets): link-button widget with createFile action

[rubenvdlinde]

Summary

Implements REQ-LBN-001..007 per spec on development.

• New LinkButtonWidget.vue — styled button renderer with three action types (external / internal / createFile); icon via IconRenderer; admin/edit-mode suppression; disabled while in flight
• New LinkButtonForm.vue — six-field sub-form (label, actionType select, url, IconPicker, bg/text colour); placeholder swaps with actionType; validate() requires label + url
• New useInternalActions.js — singleton module-level registry (register/invoke/has); warns on miss, never throws
• New POST /api/files/create — FileController + FileService with strict filename regex validation, path-traversal rejection, admin-configurable extension allow-list (txt/md/docx/xlsx/csv/odt), overwrite-on-exists semantics; three new typed exceptions
• widgetRegistry.js — added link entry with correct defaults
• i18n — 14 new keys added to en/nl .js + .json files

Test plan

• PHPUnit: 23 new tests (FileServiceTest + FileControllerTest) — all pass; pre-existing 6 DashboardShareApi errors unaffected
• Vitest: 31 new tests (LinkButtonWidget + internalActions) — 144/144 pass; pre-existing WidgetContextMenu CSS issue unchanged
• ESLint: 0 errors (24 pre-existing @SPEC warnings)
• Stylelint: clean
• PHPCS on lib/: new files all pass; 3 pre-existing failures in unrelated files

🤖 Generated with Claude Code

[github-actions]

Quality Report — ConductionNL/mydash @ 7d73be9

Check	PHP	Vue	Security	License	Tests
lint	✅
phpcs	❌
phpmd	✅
psalm	✅
phpstan	✅
phpmetrics	✅
eslint		✅
stylelint		✅
composer			✅	✅ 103/103
npm			✅	✅ 342/342
PHPUnit					⏭️
Newman					⏭️
Playwright					⏭️

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Quality workflow — 2026-04-30 20:28 UTC

Download the full PDF report from the workflow artifacts.

[github-actions]

Quality Report — ConductionNL/mydash @ 7706d61

Check	PHP	Vue	Security	License	Tests
lint	✅
phpcs	❌
phpmd	✅
psalm	✅
phpstan	✅
phpmetrics	✅
eslint		✅
stylelint		✅
composer			✅	✅ 103/103
npm			✅	✅ 342/342
PHPUnit					⏭️
Newman					⏭️
Playwright					⏭️

---

Quality workflow — 2026-04-30 20:29 UTC

Download the full PDF report from the workflow artifacts.