Overhaul Models tab UX: action feedback, post-training flow, guided navigation

- Lift modelsTab state into Zustand store so actions can navigate tabs
- Add toast notifications + auto-tab-switch to all 10 model actions
  (train, configure SFT/alignment, distill, fine-tune, quantize, eval, deploy, open-source)
- Add actionable toast buttons with navigation (e.g., "Go to Families" on training complete)
- Fix post-training config: remove 50% deadline, show until pretraining completes,
  always-visible warning prompt outside card expand, engine reminder at 75%
- PostTrainingConfig now hides already-configured sections independently
- Add tab badges: pulsing dot for active jobs, count for undeployed models, warning for no deployment
- Replace empty states with actionable buttons guiding next steps
- Stage bars show "(skip)" in warning color for unconfigured SFT/Alignment stages

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/components/common/ToastContainer.tsx

@@ -61,6 +61,19 @@ export function ToastContainer() {
             <div className="flex-1 min-w-0">
               <div className="text-sm font-medium">{toast.title}</div>
               <div className="text-xs text-surface-400">{toast.message}</div>
+              {toast.action && (
+                <button
+                  onClick={() => {
+                    if (toast.action!.page) useGameStore.getState().setActivePage(toast.action!.page);
+                    if (toast.action!.modelsTab) useGameStore.getState().setModelsTab(toast.action!.modelsTab);
+                    dismissNotification(toast.id);
+                    setToasts(prev => prev.filter(t => t.id !== toast.id));
+                  }}
+                  className="text-xs text-accent hover:text-accent-light underline mt-1"
+                >
+                  {toast.action.label}
+                </button>
+              )}
             </div>
             <button
               onClick={() => {