feat(lite): ObsidianDragonLite Network tab — server browser

A lite-wallet-only "Network" tab (full-node keeps the Peers tab; exactly one shows per variant)
to manage lightwalletd servers, replacing the basic selector that was in Settings.

- Card list of servers with per-server latency + status dot, DNS host + resolved IP, and an
  Official/Custom pill. Official DragonX servers get a glowing outline.
- Pick a server (Sticky) by clicking its card, or toggle "use a random server" (Random mode);
  selection applies immediately (App::rebuildLiteWallet(force=true) tears down + rebuilds the
  controller against the new server and resyncs — its dtor detaches the uninterruptible sync
  thread, so this doesn't block).
- Add custom servers; hide/unhide servers (persisted set, revealed by a "Show hidden" toggle).
- Latency/IP come from a new background probe (util/LiteServerProbe): libcurl CONNECT_ONLY does
  the TCP+TLS handshake (works for gRPC lightwalletd, no HTTP response needed), recording
  APPCONNECT_TIME as latency and CURLINFO_PRIMARY_IP. Auto-runs on tab open + a Refresh button.

Wiring: WalletUiSurface::LiteNetwork (gated !fullNodePagesAvailable) + NavPage::LiteNetwork in
the sidebar + app.cpp dispatch; settings gains a hidden-servers set; isOfficialLiteServer() added
to lite_connection_service. The Settings page lite-server selector + its plumbing are removed
(single source of truth = the tab).

Reuses the existing server model (LiteServerPreference, Sticky/Random, selectLiteServer) and UI
primitives (DrawGlassPanel, ThemeEffects glow, peers-tab ping-dot idiom). Unit-tested
(liteServerHost, isOfficialLiteServer) + an env-gated live probe (verified vs lite.dragonx.is:
online, latency, IP). Both variants + lite-backend build; suite passes; hygiene clean; GUI
smoke-launched without crash.

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

src/wallet/wallet_capabilities.h

@@ -42,7 +42,8 @@ enum class WalletUiSurface {
     Settings,
     BootstrapDownload,
     SetupWizard,
-    NodeSettings
+    NodeSettings,
+    LiteNetwork   // lite-wallet-only server browser (replaces Peers in lite builds)
 };
 
 struct WalletCapabilities {
@@ -153,6 +154,8 @@ constexpr bool isUiSurfaceAvailable(const WalletCapabilities& capabilities,
         case WalletUiSurface::Peers:
         case WalletUiSurface::Explorer:
             return capabilities.fullNodePagesAvailable;
+        case WalletUiSurface::LiteNetwork:
+            return !capabilities.fullNodePagesAvailable;  // lite builds only
         case WalletUiSurface::BootstrapDownload:
         case WalletUiSurface::SetupWizard:
         case WalletUiSurface::NodeSettings: