Switch auth to plain-text password env var (remove bcrypt)

- Replace ADMIN_PASSWORD_HASH with ADMIN_PASSWORD in auth route and docker-compose
- Remove bcryptjs / @types/bcryptjs dependencies
- Delete scripts/hashPassword.ts (no longer needed)

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

scripts/hashPassword.ts

@@ -1,20 +0,0 @@
-/**
- * Generates a bcrypt hash for use as ADMIN_PASSWORD_HASH env var.
- *
- * Usage:
- *   npx tsx scripts/hashPassword.ts yourpassword
- *
- * Copy the output and paste it into your Docker env var or .env file.
- */
-import bcrypt from 'bcryptjs';
-
-const password = process.argv[2];
-
-if (!password) {
-  console.error('Usage: npx tsx scripts/hashPassword.ts <password>');
-  process.exit(1);
-}
-
-bcrypt.hash(password, 12).then((hash) => {
-  console.log(hash);
-});