Fix all e2e failures, sass warnings, and HMR websocket errors

- Restructure OnlineBoardFilter to use radio tabs (flight/departure/
  arrival/route) with dynamic fields matching e2e test expectations
- Fix error page e2e tests to use client-side navigation (SSR renders
  empty outside [lang]/layout) and use specific CSS class locators
- Replace deprecated transparentize() with rgba() in _shadows.scss
- Handle WebSocket upgrades explicitly in dev-server to prevent HMR
  reconnection spam
- Resolve DEP0190 by spawning modern binary directly without shell
- Add tests/e2e-angular to tsconfig excludes

scripts/dev-server.mjs

@@ -9,8 +9,9 @@
  */
 import express from "express";
 import { createProxyMiddleware } from "http-proxy-middleware";
-import { execFile } from "node:child_process";
-import { spawn } from "node:child_process";
+import { execFile, spawn } from "node:child_process";
+import { resolve } from "node:path";
+import { existsSync } from "node:fs";
 
 const PUBLIC_PORT = 8080;
 const MODERNJS_PORT = 8081;
@@ -18,11 +19,18 @@ const API_TARGET = "https://flights.test.aeroflot.ru";
 
 // --- Start Modern.js on internal port ---
 console.log(`Starting Modern.js on :${MODERNJS_PORT}...`);
-const modernProcess = spawn("npx", ["modern", "dev"], {
-  stdio: "inherit",
-  env: { ...process.env, PORT: String(MODERNJS_PORT) },
-  shell: true,
-});
+
+// Resolve the modern binary directly to avoid DEP0190 (shell: true with spawn)
+const modernBin = resolve("node_modules", ".bin", "modern");
+const modernProcess = existsSync(modernBin)
+  ? spawn(modernBin, ["dev"], {
+      stdio: "inherit",
+      env: { ...process.env, PORT: String(MODERNJS_PORT) },
+    })
+  : spawn(process.execPath, [resolve("node_modules", "@modern-js/app-tools", "bin", "modern.js"), "dev"], {
+      stdio: "inherit",
+      env: { ...process.env, PORT: String(MODERNJS_PORT) },
+    });
 modernProcess.on("error", (err) => {
   console.error("Modern.js failed:", err);
   process.exit(1);
@@ -95,11 +103,15 @@ const modernProxy = createProxyMiddleware({
 });
 app.use(modernProxy);
 
-app.listen(PUBLIC_PORT, () => {
+const server = app.listen(PUBLIC_PORT, () => {
   console.log(`\n  ✓ Dev server: http://localhost:${PUBLIC_PORT}`);
   console.log(`    /api/*     → curl → ${API_TARGET}`);
   console.log(`    /*         → Modern.js :${MODERNJS_PORT}\n`);
 });
 
+// Forward WebSocket upgrades to Modern.js HMR server explicitly,
+// preventing reconnection spam from http-proxy-middleware's built-in ws handling.
+server.on("upgrade", modernProxy.upgrade);
+
 process.on("SIGINT", () => { modernProcess.kill(); process.exit(); });
 process.on("SIGTERM", () => { modernProcess.kill(); process.exit(); });