v5.2

AIProxy 5.2

Add optional error-only logging with request and response details in a single
append-only JSONL file.

Changes:

• Enable logging with --error-log-file ./logs/errors.jsonl. No separate toggle
  is needed; logging stays off when no filename is configured.
• Append one JSON object per HTTP 4xx/5xx response, including timestamp,
  request ID, method, path, status, response body, and original request
  headers/body. Existing log entries are preserved.
• Bound each body to 256 KiB and reuse sensitive-header and structured-secret
  redaction. Mark unreadable request bodies without disrupting the response.
• Serialize concurrent error writes and create parent directories as needed.
• Support logging.error_file in YAML and AIPROXY_ERROR_LOG_FILE in the
  environment, independently of the full request log directory.
• Document usage, privacy considerations, and limitations in README.

Successful requests and errors inside HTTP 200 SSE streams are not captured.
Logs may contain sensitive prompts and response text despite redaction;
protect the file and manage retention yourself.

Validation:

• 784 Java tests and 33 offline Python tests pass.
• Fat JAR builds with Java 21; version command reports AIProxy 5.2.
• Live provider authentication and inference were not tested for this release.

Requires Java 21 and an account with access to the selected provider/model.

Download AIProxy-5.2.jar and run:
java -jar AIProxy-5.2.jar --error-log-file ./logs/errors.jsonl

Full Changelog: v5.1...v5.2