test(sweep): capture the no-peers node banner on its full-node sweep target

renderNodeStatusBanner suppresses itself during a UI sweep (the forced demo
state would otherwise paint a banner over every tab). Add a narrow opt-in
(sweep_show_node_banner_) so ONLY the overview-no-peers target shows it; every
other capture is unchanged. The target also clears connection_in_progress_ so
the evaluator classifies the state as no-peers rather than "connecting".

Verified in a full-node + DRAGONX_ENABLE_UI_SWEEP build: the banner renders as
"Connected, but no network peers — the node can't sync · Check your internet
connection and firewall, then restart the node to find peers." (Restart button
only appears with an embedded daemon, which the sweep has none of.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app_sweep.cpp

@@ -754,8 +754,10 @@ void App::buildSweepCatalog()
             a.state_.sync.syncing = false;
             a.state_.sync.blocks = 3124322; a.state_.sync.headers = 3124322;
             a.connection_status_ = "Connected";
+            a.connection_in_progress_ = false;  // else the evaluator treats it as "connecting", not no-peers
+            a.sweep_show_node_banner_ = true;   // allow the banner (suppressed on every other target)
         },
-        resetDemoSync);
+        [resetDemoSync](App& a) { a.sweep_show_node_banner_ = false; resetDemoSync(a); });
 
     // Chat with no derived identity yet — the states that previously ALL said "unlock your wallet" (P3).
     // Setup clears the fabricated demo identity (clearIdentity wipes only the key; the demo messages stay