docs: add Tier 2 feature pages

- dashboard: container stats, system stats, historical charts, docker run converter
- resources: disk footprint widget, images/volumes/networks/unmanaged tabs, prune scopes
- app-store: template grid, category filter, deploy sheet (env vars/volumes/ports), custom registry
- global-observability: unified log stream, standard vs SSE mode, filters, capacity limits
- host-console: PTY terminal, shell type, security model, common uses
- mint.json: add all 5 new pages to Features nav group

docs/mint.json

@@ -24,8 +24,13 @@
       "group": "Features",
       "pages": [
         "features/overview",
+        "features/dashboard",
         "features/stack-management",
         "features/editor",
+        "features/resources",
+        "features/app-store",
+        "features/global-observability",
+        "features/host-console",
         "features/multi-node",
         "features/alerts-notifications"
       ]