feat(web): add global app status surface (#1869)

* feat(web): add app status bar

* feat(web): add app status bar visibility toggle

* feat(web): persist status bar item order

* fix(web): refine app status bar behavior

* fix(web): polish app status bar presentation

* test(web): split plugin slot coverage groups

* fix(web): address status surface review feedback

* fix(web): stabilize status bar overlay tests

apps/backend/internal/profiles/profiles.yaml

@@ -50,6 +50,13 @@ features:
     dev:  "true"
     e2e:  "true"
 
+  # App status bar. Off until a user opts in; on only in e2e so browser tests
+  # continuously exercise the global surface without changing user defaults.
+  KANDEV_FEATURES_APP_STATUS_BAR:
+    prod: "false"
+    dev:  "false"
+    e2e:  "true"
+
 # ── Mock providers ────────────────────────────────────────────────
 # Swap real third-party services for in-memory fakes. Production
 # leaves all of these unset (real APIs). Dev opts into the mock agent