fix(studio): Welcome layout exception, drop awkward header, Store at slot 2 (v0.39.1)

Three fixes against the v0.39.0 user feedback.

- Layout exception "BoxConstraints forces an infinite
  height". `_PillarRow`'s wide-window path used
  `Row(crossAxisAlignment: CrossAxisAlignment.stretch)`
  inside a `Column` inside a `SingleChildScrollView` — Row
  inherits unbounded height, can't stretch to anything,
  Flutter throws. Wrapped the Row in `IntrinsicHeight` so
  the Row's height is bounded to the tallest child first.
  Same shape `_DocsRow`'s narrow-window path was triggering
  with `Wrap` + `SizedBox(width: double.infinity)` — replaced
  with a plain `Column` for that path; the wide path keeps
  the Wrap with the proper finite cardWidth.

- Dropped the "WIE ES ZUSAMMENPASST" / "HOW IT FITS
  TOGETHER" section header. Operator-feedback was that the
  label sounded like a question without an answer. The hero
  already establishes the page; the three Hub/Module/Flow
  cards are self-explaining beneath it. Header was visual
  clutter and the underlying ARB keys are gone.

- Reordered the sidebar: Welcome, **Store**, Doctor, Flows,
  Audit, Approvals. Store is the operator's daily-use
  surface and belongs above Doctor (which is a diagnostics
  page). Welcome stays slot 0 as the first-launch landing.

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

lib/main.dart

@@ -26,7 +26,7 @@ import 'widgets/widgets.dart';
 /// Studio's own build version. Bump on every UI commit so the
 /// running app self-identifies — visible in the sidebar header
 /// and quick-glance proof that you're seeing the current build.
-const String kStudioVersion = '0.39.0';
+const String kStudioVersion = '0.39.1';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -146,6 +146,15 @@ class _StudioShellState extends State<StudioShell> {
       selectedIcon: Icons.waving_hand,
       page: WelcomePage(),
     ),
+    // Store moved to slot 2 in v0.39.1 — it's the
+    // operator's daily-use surface and belongs above Doctor,
+    // which is a diagnostics page.
+    _NavPage(
+      id: 'store',
+      icon: Icons.storefront_outlined,
+      selectedIcon: Icons.storefront,
+      page: StorePage(),
+    ),
     _NavPage(
       id: 'doctor',
       icon: Icons.health_and_safety_outlined,
@@ -157,12 +166,6 @@ class _StudioShellState extends State<StudioShell> {
     // the Store's detail sheet, and the Store with the
     // "Installed" filter covers the listing role. Cmd+K still
     // opens FaiModuleSheet for quick info.
-    _NavPage(
-      id: 'store',
-      icon: Icons.storefront_outlined,
-      selectedIcon: Icons.storefront,
-      page: StorePage(),
-    ),
     _NavPage(
       id: 'flows',
       icon: Icons.account_tree_outlined,