Date Picker Input Widget

[Allaoua9]

This PR is related to #2652

• Backend: new DatePicker widget class with mode, min/max, placeholder, and ISO validation, exposed via InputWidgetType.
• Frontend: DatePickerInput component (single + range) based on shadcn datepicker.
• i18n: locale-aware formatting via getDateFnsLocale plus placeholder strings in every translation file.
• Dependencies: add react-day-picker@^9.11.1 and date-fns@^4.1.0.

Single Date

Date Range :

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Summary by cubic

Added a DatePicker input widget for chat settings with single and range modes, min/max bounds, date-only ISO values, and locale-aware display.

• New Features

  • Backend: DatePicker widget with mode, initial/min/max, format, placeholder, ISO parsing/validation, date-only serialization, and InputWidgetType "datepicker".
  • Frontend: DatePickerInput (single and range) with calendar UI, confirm/reset for ranges, disabled days from bounds, and integration in FormInput.
  • i18n: locale mapping via date-fns and placeholders across all translations.

• Dependencies

  • Added react-day-picker ^9.11.1 and date-fns ^4.1.0.

^{Written for commit cc95082. Summary will update automatically on new commits.}

[cubic-dev-ai]

3 issues found across 25 files

Prompt for AI agents (all 3 issues)

Understand the root cause of the following 3 issues and fix them.


<file name="frontend/src/i18n/dateLocale.ts">

<violation number="1" location="frontend/src/i18n/dateLocale.ts:27">
The localeMap misses mappings for the existing German, Italian, and Korean locales, so getDateFnsLocale() falls back to English for those users. Please add the corresponding date-fns locales (e.g., de, it, ko) to keep date formatting aligned with the translations.</violation>
</file>

<file name="backend/chainlit/input_widget.py">

<violation number="1" location="backend/chainlit/input_widget.py:380">
`datetime.fromisoformat` returns a `datetime`, which then mixes with `date` inputs (raising `TypeError` during range checks) and serializes with a time component. Use `date.fromisoformat` so the helper always returns plain dates.</violation>
</file>

<file name="frontend/src/components/ChatSettings/DatePickerInput.tsx">

<violation number="1" location="frontend/src/components/ChatSettings/DatePickerInput.tsx:27">
If an invalid ISO string is passed into the widget, new Date(...) returns an Invalid Date without throwing. That value bubbles into format(...) and toISOString(), both of which throw a RangeError, causing the picker to crash. Guard parseDate by checking isNaN(getTime()) and returning undefined when parsing fails.</violation>
</file>

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[hayescode]

@Allaoua9 can you check the merge conflicts please

[Allaoua9]

@hayescode Done !

I've also made sure the front is sending dates instead of datetimes as this was causing undesired date shifts.