feat(web): /install shell script + real curl one-liner on landing

Landing page showed \`curl -fsSL claudemesh.sh/install | bash\` but
the domain didn't resolve, so anyone copy-pasting got a DNS error.

Ship:
- apps/web/src/app/install/route.ts: GET returns an auditable bash
  installer (Node preflight, npm install -g claudemesh-cli, runs
  claudemesh install, prints next steps, colored output). No Node
  auto-install — fails clean if missing with a pointer.
- apps/web/src/proxy.ts: exclude /install from the i18n matcher so
  Next.js returns the shell script unmangled.
- hero.tsx + features.tsx: swap claudemesh.sh → claudemesh.com.

Test: curl http://localhost:3000/install | bash -n → OK.
Content-Type: text/x-shellscript; charset=utf-8.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/proxy.ts

@@ -19,6 +19,6 @@ export const proxy = (request: NextRequest) =>
   });
 
 export const config = {
-  matcher: "/((?!api|static|.*\\..*|_next).*)",
+  matcher: "/((?!api|static|install|.*\\..*|_next).*)",
   unstable_allowDynamic: ["**/node_modules/lodash*/**/*.js"],
 };