fix: resolve platform authentication cookie conflicts and session management

- Fix cookie isolation between regular and platform authentication systems
- Add custom cookie names for regular auth (app-auth.session-token) vs platform auth (platform-auth.session-token)
- Remove restrictive cookie path from platform auth to allow proper session access
- Create custom usePlatformSession hook to bypass NextAuth useSession routing issues
- Fix platform dashboard authentication and eliminate redirect loops
- Add proper NEXTAUTH_SECRET configuration
- Enhance platform login with autocomplete attributes
- Update TODO with PR #20 feedback actions and mark platform features complete

The platform management dashboard now has fully functional authentication
with proper session isolation between regular users and platform admins.

lib/platform-auth.ts

@@ -79,7 +79,7 @@ export const platformAuthOptions: NextAuthOptions = {
       options: {
         httpOnly: true,
         sameSite: "lax",
-        path: "/platform",
+        path: "/",
         secure: process.env.NODE_ENV === "production",
       },
     },