Header logging toggle and batching sink fix

Summary

• add a logHeaders(enabled) builder toggle, defaulting to true, for request and response header sections
• add the missing response header block under Status Code: while keeping existing Body: behavior unchanged
• isolate BatchingSink buffers by tag and current thread to avoid concurrent same-tag corruption and StringIndexOutOfBoundsException
• add JVM tests covering request/response header output and concurrent batching isolation

Included commits

• 9496108 Add response header logging and isolate sink buffers
• 9ecd68d Rename header toggle to logHeaders
• 6d81aaa Remove default note from README examples

Verification

• .\\gradlew.bat :lib:test :lib:build

Upstream PR

• ihsanbal/LoggingInterceptor#100