Sink Write Modes

.append grows the file, .overwrite truncates on startup, .appendRotate appends with rotation triggers. JSON sinks respect the mode too.

_ = try logger.addSink(.{ .path = "logs/app.log", .writeMode = .append });
_ = try logger.addSink(.{ .path = "logs/session.log", .writeMode = .overwrite });

Resulting files:

logs/
├── append_mode.log      (growing file)
├── overwrite_mode.log   (fresh each run)
├── persistent.log       (all history)
├── session.log          (current run only)
└── logs.json            (JSON array)