fix(layout): add flex flex-col to ViewTransitionOutlet — fixes action bar visibility

Root cause: ViewTransitionOutlet wrapping <Outlet> had flex-1 min-h-0 but
display:block (no flex flex-col). Child pages using h-full flex-col couldn't
resolve height against a block parent, so content overflowed and the
FlowPilot action bar (Resolve/Escalate/Pause) rendered below the viewport.

Fix: Add flex flex-col to the outlet wrapper so the full flex height chain
works: app-shell grid → main flex-col → outlet flex-col → page flex-col.

Also removed the h-0 workaround from FlowPilotSessionPage since this
addresses the actual root cause.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/layout/ViewTransitionOutlet.tsx

@@ -19,7 +19,7 @@ export function ViewTransitionOutlet() {
   const routeKey = segments.slice(0, 2).join('/') || '/'
 
   return (
-    <div key={routeKey} className="flex-1 min-h-0 animate-fade-in-up">
+    <div key={routeKey} className="flex-1 min-h-0 flex flex-col animate-fade-in-up">
       <Outlet />
     </div>
   )