Privacy Policy page + Chat API key fix

- /privacy page for Google Play (GDPR compliant)
- Fixed Anthropic API key mismatch in .env
- Chat returns AI responses again

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/upload-release.sh

@@ -5,7 +5,7 @@ set -euo pipefail
 
 VERSION=${1:-$(date +%Y%m%d_%H%M)}
 PLATFORM=${2:-android}
-FILE=$3
+FILE=${3:-}
 
 if [ -z "${FILE:-}" ]; then
     echo "Usage: upload-release.sh <version> <platform> <file>"