Implement AssignedContactsList scrollable section

Define AssignedContactsList as a StatelessWidget with parameters: List contacts, void Function(String contactId) onContactTap, and an optional String sectionTitle. Use ListView.builder(shrinkWrap: true, physics: const NeverScrollableScrollPhysics(), ...) for correct embedding in CustomScrollView. The shrinkWrap: true is necessary when the list is a child of a Column inside a CustomScrollView — document this constraint in code comments. For the status indicator, use a Container with a circular shape and a color derived from a switch on AssignedContact.assignmentStatus — map status enum values to design token colors.

For the empty state, create a simple EmptyContactsState widget (reuse or create new) with a neutral icon (e.g., Icons.people_outline) and the text 'No assigned contacts yet'. Keep the row widget as a private _ContactRow StatelessWidget inside the same file for encapsulation. Define the AssignedContact data class with the fields above, or reuse an existing model if one exists — check the codebase before creating a new one.

Write widget tests using flutter_test. Test 1: pass an empty list — assert the empty-state widget is present and no ListTile/Row widgets are rendered. Test 2: pass a list of 3 contacts — assert exactly 3 row widgets are rendered and each displays the correct name. Test 3: tap the first row — assert onContactTap is called with the correct contact ID.

Test 4: verify NeverScrollableScrollPhysics is applied by checking widget type in the tree. Test 5: pass 100 contacts — assert the widget builds without overflow errors (use tester.pump() and check for no exceptions). Use pump() not pumpAndSettle() to avoid timeout on large lists.