feat(studio): real install progress in the store dialog and the wizard

Both surfaces showed an indeterminate spinner for the whole install,
because the hub only offered a unary call. They now follow
HubAdmin/InstallModuleStream:

- The store's install dialog shows the phase in plain language, the
  overall percentage, megabytes while the size is known, and a seconds
  counter. The counter is the second, independent signal: it keeps
  running even if the hub goes quiet, which is what tells 'slow' apart
  from 'stuck'.
- The setup wizard shows the same bar per module instead of a spinner
  inside the button.
- New strings in both locales for the phases, the byte line and the
  elapsed counter.

progress_bar_visual_test writes the four waiting states to
build/progress/ in either theme, so the result can be judged without
launching the desktop app. Writing it turned up a real trap worth
recording: awaiting toImage() directly in a widget test leaves the
binding waiting forever - the file passed in six seconds, then sat
there until the ten-minute timeout failed the whole suite.
tester.runAsync() is the fix. Full suite: 186 passed.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/data/hub.dart

@@ -972,6 +972,34 @@ class HubService {
     return (name: r.name, version: r.version);
   }
 
+  /// Install a module while watching it happen.
+  ///
+  /// Emits one [InstallStep] per phase change and, during the
+  /// download, as bytes arrive. Completes when the install
+  /// succeeds; throws the hub's error otherwise, exactly like
+  /// [installModule]. [onFinished] receives name and version.
+  Stream<InstallStep> installModuleStreaming({
+    required String source,
+    void Function(({String name, String version}) result)? onFinished,
+  }) {
+    return _client
+        .installModuleStreaming(
+          source: source,
+          onFinished: (r) => onFinished?.call((name: r.name, version: r.version)),
+        )
+        .map(
+          (u) => InstallStep(
+            phase: u.phase,
+            // `percent` is absent while the extent is unknowable; the
+            // bar shows that as indeterminate rather than as zero.
+            percent: u.hasPercent() ? u.percent : null,
+            bytesReceived: u.bytesReceived.toInt(),
+            bytesTotal: u.bytesTotal.toInt(),
+            phaseDone: u.phaseDone,
+          ),
+        );
+  }
+
   /// The shared hub's project registry (`general` first) — the
   /// lightweight labels grouping flows, runs, approvals and audit
   /// events. Sealed areas never appear here: they are their own
@@ -1545,6 +1573,40 @@ class ModuleSummary {
 /// slug plus renamable presentation metadata. `isolation` is
 /// `open` (pure label) or `protected` (logically separated — no
 /// hard process barrier; every UI keeps that honest wording).
+/// One observation while a module installs.
+///
+/// [percent] is the overall value across all phases and may stand
+/// still for a long time during a big download; that is expected and
+/// is why the bar carries its own sign of life. A null [percent]
+/// means the extent isn't knowable yet.
+class InstallStep {
+  /// Stable phase id: `resolve`, `download` or `install`.
+  final String phase;
+
+  /// Overall progress 0..100, or null while indeterminate.
+  final double? percent;
+
+  /// Bytes received so far (download phase only).
+  final int bytesReceived;
+
+  /// Total bytes announced by the server; 0 when unknown.
+  final int bytesTotal;
+
+  /// This phase just finished.
+  final bool phaseDone;
+
+  const InstallStep({
+    required this.phase,
+    required this.percent,
+    required this.bytesReceived,
+    required this.bytesTotal,
+    required this.phaseDone,
+  });
+
+  /// True while the server told us how big the download is.
+  bool get hasSize => bytesTotal > 0;
+}
+
 class ProjectRef {
   final String slug;
   final String name;