feat(ui): let the user choose newest or oldest first

Two entries, straight to notmuch. This adds a feature rather than replacing one:
the column header was decorative and nothing implemented click-to-sort, so
removing the header with the grid lost nothing.

Stored in uistate.conf, never in the hand-edited config, and range-guarded on
read: a stale file can hold anything, which is the lesson item 58 recorded.

SortOrder needed qRegisterMetaType despite carrying Q_ENUM. Q_ENUM gives the
enum a meta-object entry, not a metatype registered under the name invokeMethod
resolves, so the queued runQuery would have dropped its sort argument at runtime
and every query would have silently run newest-first. Nothing in the suite
exercises a real worker thread, so this was asserted directly rather than left
to a warning nobody would see. It is registered beside the type rather than in
MainWindow's constructor: a first attempt put it there and passed only because
the test that catches it never constructs a MainWindow.

The account dropdown's entries now carry their account's colour as a swatch,
which is what makes the accent bar on a card mean anything: a colour down a
card's edge says nothing until something maps it to a name. Raw colour here
rather than the blended line colour, since a swatch is a filled patch like a
chip rather than a thin line. Its test builds its own two-account config: reading
the environment's made it SKIP wherever no accounts are configured, which is a
test that asserts nothing while reporting success.

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/test_notmuchworker.cpp b/tests/test_notmuchworker.cpp
index 3342013..88dcf0b 100644
--- a/tests/test_notmuchworker.cpp
+++ b/tests/test_notmuchworker.cpp
@@ -40,6 +40,7 @@ private slots:
     void unreadableConfigEmitsError();
     void queryPassesGenerationThrough();
     void oldestFirstReversesTheOrder();
+    void theSortOrderCrossesAQueuedCall();
 
     void loadThreadReturnsMessagesOldestFirst();
     void loadThreadMarksMatchedMessages();
@@ -346,6 +347,27 @@ void TestNotmuchWorker::oldestFirstReversesTheOrder()
     QCOMPARE(oldest.last().threadId, newest.first().threadId);
 }
 
+void TestNotmuchWorker::theSortOrderCrossesAQueuedCall()
+{
+    // MainWindow reaches the worker with invokeMethod(..., QueuedConnection)
+    // across a thread boundary, and a Q_ARG whose type the meta-object system
+    // does not know FAILS AT RUNTIME with a warning, not at compile time. So
+    // the enum's registration is asserted here rather than assumed from Q_ENUM.
+    QVERIFY2(QMetaType::fromName("NotmuchWorker::SortOrder").isValid(),
+             "SortOrder is not a registered metatype, so the queued runQuery "
+             "call will drop its sort argument at runtime");
+
+    NotmuchWorker worker(m_fixture.configPath());
+    QSignalSpy ready(&worker, &NotmuchWorker::threadsReady);
+
+    // The real call shape, invoked by NAME exactly as MainWindow does.
+    QVERIFY(QMetaObject::invokeMethod(
+        &worker, "runQuery", Qt::DirectConnection,
+        Q_ARG(QString, QStringLiteral("*")), Q_ARG(quint64, 1),
+        Q_ARG(NotmuchWorker::SortOrder, NotmuchWorker::OldestFirst)));
+    QCOMPARE(ready.size(), 1);
+}
+
 void TestNotmuchWorker::loadThreadReturnsMessagesOldestFirst()
 {
     const QString threadId = threadIdOf(QStringLiteral("Release notes"));