compose [nfc]: Take UserStore in userMention, rather than bare Map

Now that we have a UserStore type, we can give this a bit more
abstraction.

Author: gnprice

lib/model/compose.dart

@@ -5,6 +5,7 @@ import '../generated/l10n/zulip_localizations.dart';
 import 'internal_link.dart';
 import 'narrow.dart';
 import 'store.dart';
+import 'user.dart';
 
 /// The available user wildcard mention options,
 /// known to the server as [canonicalString].
@@ -127,11 +128,12 @@ String wrapWithBacktickFence({required String content, String? infoString}) {
 /// An @-mention of an individual user, like @**Chris Bobbe|13313**.
 ///
 /// To omit the user ID part ("|13313") whenever the name part is unambiguous,
-/// pass a Map of all users we know about. This means accepting a linear scan
+/// pass the full UserStore.  This means accepting a linear scan
 /// through all users; avoid it in performance-sensitive codepaths.
-String userMention(User user, {bool silent = false, Map<int, User>? users}) {
+String userMention(User user, {bool silent = false, UserStore? users}) {
   bool includeUserId = users == null
-    || users.values.where((u) => u.fullName == user.fullName).take(2).length == 2;
+    || users.users.values.where((u) => u.fullName == user.fullName)
+         .take(2).length == 2;
 
   return '@${silent ? '_' : ''}**${user.fullName}${includeUserId ? '|${user.userId}' : ''}**';
 }

lib/widgets/autocomplete.dart

@@ -202,7 +202,7 @@ class ComposeAutocomplete extends AutocompleteField<ComposeAutocompleteQuery, Co
         }
         // TODO(i18n) language-appropriate space character; check active keyboard?
         //   (maybe handle centrally in `controller`)
-        replacementString = '${userMention(store.users[userId]!, silent: query.silent, users: store.users)} ';
+        replacementString = '${userMention(store.users[userId]!, silent: query.silent, users: store)} ';
       case WildcardMentionAutocompleteResult(:var wildcardOption):
         replacementString = '${wildcardMention(wildcardOption, store: store)} ';
     }

test/model/compose_test.dart

@@ -234,17 +234,17 @@ hello
       test('`users` passed; has two users with same fullName', () async {
         final store = eg.store();
         await store.addUsers([user, eg.user(userId: 5), eg.user(userId: 234, fullName: user.fullName)]);
-        check(userMention(user, silent: true, users: store.users)).equals('@_**Full Name|123**');
+        check(userMention(user, silent: true, users: store)).equals('@_**Full Name|123**');
       });
       test('`users` passed; has two same-name users but one of them is deactivated', () async {
         final store = eg.store();
         await store.addUsers([user, eg.user(userId: 5), eg.user(userId: 234, fullName: user.fullName, isActive: false)]);
-        check(userMention(user, silent: true, users: store.users)).equals('@_**Full Name|123**');
+        check(userMention(user, silent: true, users: store)).equals('@_**Full Name|123**');
       });
       test('`users` passed; user has unique fullName', () async {
         final store = eg.store();
         await store.addUsers([user, eg.user(userId: 234, fullName: 'Another Name')]);
-        check(userMention(user, silent: true, users: store.users)).equals('@_**Full Name**');
+        check(userMention(user, silent: true, users: store)).equals('@_**Full Name**');
       });
     });
 

test/widgets/autocomplete_test.dart

@@ -174,7 +174,7 @@ void main() {
       await tester.tap(find.text('User Three'));
       await tester.pump();
       check(tester.widget<TextField>(composeInputFinder).controller!.text)
-        .contains(userMention(user3, users: store.users));
+        .contains(userMention(user3, users: store));
       checkUserShown(user1, store, expected: false);
       checkUserShown(user2, store, expected: false);
       checkUserShown(user3, store, expected: false);