✨ Add timeSlotColorBuilder in MultiDayView

[lavigarg-simform]

Description

Extends the existing timeSlotColorBuilder feature (previously available only in DayView and WeekView) to MultiDayView, and extracts the duplicated slot-background building logic into a single shared TimeSlotBackgrounds widget used by all three calendar views.

Changes

Feature — timeSlotColorBuilder in MultiDayView

• MultiDayView (multi_day_view.dart): Added timeSlotColorBuilder parameter (TimeSlotColorBuilder?), threaded it through to InternalMultiDayViewPage.
• InternalMultiDayViewPage (_internal_multi_day_view_page.dart): Renders the slot-background layer inside the scrollable Stack when timeSlotColorBuilder is non-null, producing one coloured column per visible day.
• Example (multi_day_view_widget.dart): Added a timeSlotColorBuilder usage example to the demo app (highlights business hours, lunch breaks, and weekends).

Refactor — Shared TimeSlotBackgrounds widget

The inline implementations of _buildTimeSlotBackground (DayView), _buildWeekTimeSlotBackgrounds (WeekView), and _buildMultiDayTimeSlotBackgrounds (MultiDayView) were all functionally equivalent column-painting logic. They have been replaced with a single shared widget:

• TimeSlotBackgrounds added to common_components.dart:
  • Accepts a List<DateTime> dates (one column per date), so it works for single-day and multi-column layouts.
  • Computes slot heights, total slot count, and per-slot colors internally.
  • Wraps each column in ClipRect + RepaintBoundary to isolate repaints.
  • Respects RTL (Directionality) layout.
• _internal_day_view_page.dart: _buildTimeSlotBackground() now delegates to TimeSlotBackgrounds(dates: [widget.date], ...). Pre-existing unused extensions.dart import removed.
• _internal_week_view_page.dart: _buildWeekTimeSlotBackgrounds() now delegates to TimeSlotBackgrounds.
• _internal_multi_day_view_page.dart: _buildMultiDayTimeSlotBackgrounds() now delegates to TimeSlotBackgrounds.

Tests

• time_slot_color_builder_test.dart: Added a MultiDayView test case that verifies:
  • The timeSlotColorBuilder is invoked for every slot on every visible day column (12 unique date-time slot starts for 3 days × 4 half-hour slots in a 9–11 window).
  • Each day produces its own TimeSlotBackgroundPainter (findsNWidgets(3)).
  • Assertions are date-independent since MultiDayView aligns page boundaries relative to DateTime.now().

Checklist

• The title of my PR starts with a [Conventional Commit] prefix (fix:, feat:, docs: etc).
• I have followed the [Contributor Guide] when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples or docs.

Breaking Change?

• Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

Related Issues

Closes #535

[Copilot]

Pull request overview

Adds timeSlotColorBuilder support to MultiDayView to match the existing DayView/WeekView API, enabling per-slot background coloring for business hours, blocked time, etc.

Changes:

• Exposes timeSlotColorBuilder on MultiDayView and wires it through to the internal page implementation.
• Renders painted slot background layers in InternalMultiDayViewPage when the builder is provided.
• Updates the example and changelog to reflect the new capability.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
lib/src/multi_day_view/multi_day_view.dart	Adds the public timeSlotColorBuilder parameter and passes it into the internal page.
lib/src/multi_day_view/_internal_multi_day_view_page.dart	Implements slot background painting for MultiDayView using TimeSlotBackgroundPainter.
example/lib/widgets/multi_day_view_widget.dart	Demonstrates usage of timeSlotColorBuilder in MultiDayView.
CHANGELOG.md	Notes MultiDayView support for timeSlotColorBuilder.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.