fix(realtime): CI gate fixes surfaced by Phase 11 smoke tests

- no-direct-socket-io: extend allowlist to cover apps/*/src/**/*.test.ts so
  the realtime-ping e2e integration test can import socket.io/socket.io-client
  directly; add two valid test cases to keep the rule's own test suite green
- tsconfig.json (root): add root-level tsconfig with experimentalDecorators +
  emitDecoratorMetadata and no "include" so tsx 4.21.0's createFilesMatcher
  resolves decorator config for all workspace packages, not just web-next's
  own source tree
- web-next dev script: pass TSX_TSCONFIG_PATH=../../tsconfig.json so the
  custom Node server uses the root tsconfig for all modules it loads
- next.config.mjs: add @repo/core-events and @repo/core-realtime to
  transpilePackages so Next.js webpack can resolve their workspace source files
- server.ts: replace static authContainer import with a dynamic import inside
  IRealtimeAuthenticator.authenticate so Inversify decorators are applied only
  after bindAll() has already populated the container

All CI gates pass: lint (0 errors), typecheck, 20 tests (incl. realtime-ping
e2e), boundaries (0 issues).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-eslint/rules/no-direct-socket-io.js

@@ -2,6 +2,7 @@
 const ALLOWED = [
   /\/packages\/core-realtime\/src\//,
   /\/apps\/[^/]+\/server\.ts$/,
+  /\/apps\/[^/]+\/src\/.*\.test\.ts$/,
 ];
 
 export default {

packages/core-eslint/rules/no-direct-socket-io.test.js

@@ -12,6 +12,9 @@ tester.run("no-direct-socket-io", rule, {
     { code: 'import { Server } from "socket.io";', filename: "/repo/packages/core-realtime/src/socket-io-realtime-server.ts" },
     // Allowed in app servers
     { code: 'import { Server } from "socket.io";', filename: "/repo/apps/web-next/server.ts" },
+    // Allowed in app integration tests (e.g. realtime-ping e2e)
+    { code: 'import { Server } from "socket.io";', filename: "/repo/apps/web-next/src/__tests__/realtime-ping.test.ts" },
+    { code: 'import { io } from "socket.io-client";', filename: "/repo/apps/web-next/src/__tests__/realtime-ping.test.ts" },
     // Allowed elsewhere when not importing socket.io
     { code: 'import { foo } from "bar";', filename: "/repo/packages/blog/src/foo.ts" },
   ],