Add keyboard dismiss toolbar for iOS numeric and multi-line fields

Creates a reusable KeyboardDismissToolbar view modifier that adds a
"Done" button to dismiss keyboards that don't have a return key.
Applied to all numeric keyboards (numberPad, decimalPad, phonePad)
and multi-line text inputs (TextEditor, TextField with axis: .vertical).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

iosApp/iosApp/Contractor/ContractorFormSheet.swift

@@ -112,6 +112,7 @@ struct ContractorFormSheet: View {
                         TextField(L10n.Contractors.phoneLabel, text: $phone)
                             .keyboardType(.phonePad)
                             .focused($focusedField, equals: .phone)
+                            .keyboardDismissToolbar()
                     }
 
                     HStack {
@@ -203,6 +204,7 @@ struct ContractorFormSheet: View {
                             .keyboardType(.numberPad)
                             .focused($focusedField, equals: .postalCode)
                             .frame(maxWidth: 100)
+                            .keyboardDismissToolbar()
                     }
                 } header: {
                     Text(L10n.Contractors.addressSection)
@@ -220,6 +222,7 @@ struct ContractorFormSheet: View {
                         TextEditor(text: $notes)
                             .frame(height: 100)
                             .focused($focusedField, equals: .notes)
+                            .keyboardDismissToolbar()
                     }
                 } header: {
                     Text(L10n.Contractors.notesSection)