gui: Options — Capture tab, saveTo.allowedRoots, lock coverage to the schema

Options was missing 8 of the 43 real settings.* keys: capture.enabled,
monitoredExtensions, monitoredMimeTypes, minSizeBytes, excludedHosts,
bypassModifier, autoStartTypes, and saveTo.allowedRoots. The capture.* keys
were dropped in an earlier pass on the mistaken read that the spec's "File
Types" tab meant per-category extension lists (which do live on Category,
not settings.*) — they're real settings.* keys for a real daemon feature
(the extension's auto-capture policy), so the tab exists now, named
"Capture" to match what it actually configures rather than the spec's
label.

New tst_optionsdialog case (allKeysMatchesTheSchemaExactly) loads
Settings.schema.json itself at test time and diffs its property set against
OptionsDialog::allKeys() — this drifted silently once already, so the
regression is now a build-time gate an unused import or a future key
addition would trip, not something that needs re-discovering by hand again.

Verified against a real veloxd (not just mockd): settings.get across all
43 keys, a settings.set/get round trip on a scalar (connection.timeoutSec)
and on array-valued keys in the shapes OptionsDialog::currentValues()
actually produces (capture.monitoredExtensions, proxy.bypassHosts,
saveTo.allowedRoots), and event.settings.changed fanning out to a second
subscribed client — all round-tripped and restored to their original
values afterward. The real OptionsDialog widget also loads and renders
correctly against that same daemon's live defaults with no crash under
ASan+UBSan.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NSCdCWFXBTSBBK3MzWtJiC

gui/tests/tst_optionsdialog.cpp

@@ -5,6 +5,8 @@
 // effect" contract and spams event.settings.changed with noise), or a key present in
 // `current` but absent from `original` stops being treated as changed.
 
+#include <QFile>
+#include <QJsonDocument>
 #include <QJsonObject>
 #include <QtTest>
 
@@ -20,6 +22,7 @@ class TstOptionsDialog : public QObject {
     void onlyChangedKeysAreReturned();
     void keyAbsentFromOriginalCountsAsChanged();
     void allKeysAreNonEmptyAndUnique();
+    void allKeysMatchesTheSchemaExactly();
 };
 
 void TstOptionsDialog::identicalValuesProduceNoDiff() {
@@ -50,5 +53,24 @@ void TstOptionsDialog::allKeysAreNonEmptyAndUnique() {
     QCOMPARE(QSet<QString>(keys.begin(), keys.end()).size(), keys.size());
 }
 
+// Red when a key is added to (or removed from) Settings.schema.json without the same
+// change landing here — either direction is a real bug: an invented key settings.set
+// would reject with -32602, or a real key the dialog silently never shows.
+void TstOptionsDialog::allKeysMatchesTheSchemaExactly() {
+    QFile f(QStringLiteral(VELOX_REPO_ROOT "/contracts/schema/types/Settings.schema.json"));
+    QVERIFY2(f.open(QIODevice::ReadOnly), qUtf8Printable(f.errorString()));
+    const QJsonObject schema = QJsonDocument::fromJson(f.readAll()).object();
+    const QJsonObject properties = schema.value("properties").toObject();
+    QVERIFY(!properties.isEmpty());
+
+    QSet<QString> schemaKeys;
+    for (auto it = properties.constBegin(); it != properties.constEnd(); ++it) {
+        schemaKeys.insert(it.key());
+    }
+    const QStringList dialogKeysList = OptionsDialog::allKeys();
+    const QSet<QString> dialogKeys(dialogKeysList.begin(), dialogKeysList.end());
+    QCOMPARE(dialogKeys, schemaKeys);
+}
+
 QTEST_MAIN(TstOptionsDialog)
 #include "tst_optionsdialog.moc"