v0.6.2

Fixes

Stop slow ALTCHA solves from rejecting real submissions (#8)

Visitors could be rejected with "Sorry, your submission could not be verified" even though they did nothing wrong:

• auto="onload" only starts the proof. Submitting before it finished posted an empty altcha field (logged as reason: missing), and the AJAX re-render restarted the proof from zero, so quick retries failed the same way.
• A solve that hit the widget's 90s timeout (Failed to find solution.) was never retried.

Now:

• Gravity Forms submissions wait for the proof via the async gform/submission/pre_submission filter (GF's spinner stays up meanwhile).
• A failed solve is retried with a fresh challenge, up to 3 times. If it still fails, the submission goes ahead and the server shows its "reload and try again" message.

Realistic protection-strength labels

Browser WebCrypto PBKDF2 runs roughly 1M iterations/s per core, so Very high (1M) averages ~25s on a fast desktop and exceeds the 90s timeout on ordinary laptops. The dropdown labels and README now say so; prefer Standard unless a form is under real attack.

Full changelog: v0.6.1...v0.6.2