fix(ci): eliminate test-crates build warnings

Correct dead platform declarations, stale rustdoc and test warnings; validate complete gettext headers. Install LLD in the Qt job and explicitly validate committed shader packs without rebaking them. Keep the independent shader bake gate and add three build-policy tests.

The full local gate passed 2398 workspace tests and 715 Qt tests, QML audits, shader baking and the isolated offscreen smoke without compiler, rustdoc or gettext warnings.

cx

crates/qbz-qt/src/deep_link_qt.rs

@@ -74,6 +74,7 @@ fn select_link(args: &[String]) -> Option<String> {
 ///
 /// The single-instance server feeds it whatever arrived on the pipe, which is
 /// not argv and is not ours.
+#[cfg(any(target_os = "windows", test))]
 pub(crate) fn is_actionable(url: &str) -> bool {
     if !is_qobuz_link(url) && !url.starts_with("qbz://") {
         return false;