feat(worker): list every tag in the database

Query bar completion cannot offer tag names without a way to enumerate
them, and libnotmuch had no call wired up for it. Follows the existing
generation-counter pattern; the result crosses the thread boundary as a
QStringList.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/notmuchworker.cpp b/src/notmuchworker.cpp
index ed97e39..a5096d2 100644
--- a/src/notmuchworker.cpp
+++ b/src/notmuchworker.cpp
@@ -332,3 +332,24 @@ void NotmuchWorker::applyTags(const TagChange &change)
 
     emit tagsApplied(change);
 }
+
+void NotmuchWorker::requestAllTags(quint64 generation)
+{
+    if (!openReadOnly())
+        return;
+
+    NmTags tags(notmuch_database_get_all_tags(m_db));
+    if (!tags) {
+        emit errorOccurred(QStringLiteral("Cannot list tags"));
+        return;
+    }
+
+    QStringList result;
+    for (; notmuch_tags_valid(tags.get()); notmuch_tags_move_to_next(tags.get()))
+        result.append(QString::fromUtf8(notmuch_tags_get(tags.get())));
+
+    // Sorted once here so no consumer has to sort again. notmuch returns tags
+    // in Xapian term order, which is byte order, not the user's locale order.
+    result.sort();
+    emit allTagsReady(result, generation);
+}