fix(ui): resolve hydration mismatch, infinite loop, and missing assets

- Add suppressHydrationWarning to <html>/<body>/<div.app> to suppress
  server/client theme+lang state differences during SSR hydration
- Add mounted gate in ClientLayout so PWA/call modals only render
  client-side, eliminating React #418 hydration error
- Rewrite useI18n hook with stable module-level subscribe functions and
  useRef-cached t() to eliminate React #185 infinite update loop
- Copy static/ assets (favicon, logo, hero, fonts, sw.js, etc.) to
  public/ so Next.js serves them — fixes inter-var.woff2 404

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

Author: ralyodio

public/.well-known/security.txt

@@ -0,0 +1,4 @@
+Contact: mailto:security@qrypt.chat
+Expires: 2027-06-02T00:00:00.000Z
+Preferred-Languages: en
+Canonical: https://qrypt.chat/.well-known/security.txt

public/banner.png

@@ -0,0 +1,16 @@
+/* TEAM */
+Developer: Profullstack, Inc.
+Site: https://profullstack.com
+Location: USA
+
+/* THANKS */
+Node.js community
+
+/* SITE */
+Last update: 2025/01/05
+Standards: ES2024+, ESM
+Components: Node.js, Mocha, Chai, ESLint, Prettier
+Software: VS Code
+
+/* SPEC */
+humans.txt spec: https://humanstxt.org/