Initial commit: thbd-portal, duplicated from elmi-portal

Rebranded for Thunderbird Portal (THBD): numbering prefix EL->TH, all
"ELMI"/"ЭЛМИ" UI strings genericized, ELMI's real contract templates and
company legal/bank details removed (not applicable to this company), fresh
VAPID keypair and encryption key, fresh single-migration schema history.
Same architecture as elmi-portal: Web Push notifications, unread-chat app
badge, cookie-session auth.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gh2UXUQUVBWroWEnn1FLFG

eslint.config.mjs

@@ -0,0 +1,16 @@
+import { defineConfig, globalIgnores } from "eslint/config";
+import nextVitals from "eslint-config-next/core-web-vitals";
+import nextTs from "eslint-config-next/typescript";
+
+const eslintConfig = defineConfig([
+  ...nextVitals,
+  ...nextTs,
+  globalIgnores([
+    ".next/**",
+    "out/**",
+    "build/**",
+    "next-env.d.ts",
+  ]),
+]);
+
+export default eslintConfig;