refactor(app): remove unsupported server selector state (#6)

Remove UI and provider state that does not control the authoritative tunnel destination while preserving the existing connection-health status behavior.

lib/screens/server_selector/selection_screen.dart

@@ -1,63 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:provider/provider.dart';
-import 'package:revoltvpn/logic/app_colors.dart';
-import 'package:revoltvpn/logic/server_list.dart';
-
-// ── lib/screens/server_selector/selection_screen.dart ──────────────────────
-// Server picker — reads the server list from the ServerList provider.
-// Each row shows a flag + city name.  Tapping a row persists the choice
-// and pops back.  No latency measurement — the app runs inside a Reality
-// tunnel and must not emit separate probe traffic.
-
-class SelectionScreen extends StatelessWidget {
-  const SelectionScreen({super.key});
-
-  @override
-  Widget build(BuildContext context) {
-    final serverList = context.watch<ServerList>();
-
-    return Scaffold(
-      backgroundColor: AppColors.bgDeep,
-      appBar: AppBar(
-        backgroundColor: AppColors.bgSurface,
-        elevation: 0,
-        leading: IconButton(
-          icon: const Icon(Icons.arrow_back, color: AppColors.textWhite),
-          onPressed: () => Navigator.of(context).pop(),
-        ),
-        title: const Text(
-          'Select Server',
-          style: TextStyle(
-            color: AppColors.textWhite,
-            fontWeight: FontWeight.w600,
-          ),
-        ),
-      ),
-      body: ListView.builder(
-        itemCount: serverList.all.length,
-        itemBuilder: (context, index) {
-          final server = serverList.all[index];
-          final isSelected = index == serverList.selectedIndex;
-
-          return ListTile(
-            leading: Image.asset(server.flagAsset, width: 28, height: 28),
-            title: Text(server.name,
-                style: TextStyle(
-                  color: isSelected ? AppColors.accent : AppColors.textWhite,
-                  fontWeight: FontWeight.w600,
-                )),
-            trailing: isSelected
-                ? const Icon(Icons.check, color: AppColors.accent)
-                : null,
-            onTap: () {
-              serverList.select(index);
-              Navigator.of(context).pop();
-            },
-            contentPadding:
-                const EdgeInsets.symmetric(horizontal: 20, vertical: 8),
-          );
-        },
-      ),
-    );
-  }
-}