Motivation

• Provide a mobile-only floating action button (FAB) in the bottom-left so users can quickly add income or expense entries from any view on small screens.
• Reuse existing save/refresh logic so both the dashboard form and the new mobile quick-add behave the same and keep UI consistent.

Description

• Added a blue floating button and a mobile-only modal form in index.html that appears on screens <768px (#mobileQuickAddBtn, #mobileQuickAddModal).
• Implemented wiring and behavior in script.js: new DOM refs, mobileQuickDatePicker (Flatpickr), addMobileQuickEntry, updateMobileQuickCategoryOptions, openMobileQuickAdd, closeMobileQuickAdd, and resetMobileQuickAddForm.
• Refactored transaction creation/refresh into shared helpers saveTransaction and refreshAfterTransactionAdded and updated the dashboard form to use them so both forms save consistently.
• Kept mobile-only visibility safe without requiring a Tailwind rebuild by adding inline CSS fallbacks that force the FAB/modal to be hidden on desktop and visible on small screens.

Testing

• node --check script.js ran and returned no syntax errors (success).
• git diff --check was run to validate whitespace/patch issues (success).
• npm ci failed due to registry permission errors (403 Forbidden for a dependency), so node modules could not be restored in this environment (failed).
• npm run build:css could not complete because the Tailwind CLI was unavailable in the environment (failed), so inline mobile-only CSS was added to avoid requiring a rebuild.

Codex Task