Revert BERT label to probs[0][0] (correct AI index), expose perplexity in response schema

Fix model accuracy: correct BERT label, reduce temperature, add perplexity signal, fix TTR for short texts

Fix: remove duplicate BertScorer class, correct torch version, fix CORS origins

Fix health check attribute and remove perplexity scorer

Rename dockerfile to Dockerfile

Initial deploy — AI text detector API