Build a logging framework with levels and sinks

• Levels DEBUG, INFO, WARN, ERROR with ordering; a logger drops messages below its configured level
• Named loggers (for example getLogger("db")) with per-logger level overrides and inheritance from a root configuration
• Multiple sinks per logger (console, file, in-memory for tests), each with its own minimum level
• Formatters are pluggable: a text formatter (timestamp, level, name, message) and a JSON formatter, chosen per sink
• Structured context: logger.info(msg, { userId }) and child loggers that carry bound fields on every entry
• Errors passed as context are serialised with message and stack
• Async buffering: file writes are batched and flushed on an interval, when the buffer reaches a size, and on process exit; a failing sink never throws into application code

Only after every requirement works.

• Log rotation by size or date
• Sampling for noisy messages
• Correlation id propagation with AsyncLocalStorage