Address code review feedback for log rotation implementation

[Copilot]

Addressed 9 code review comments on the initial log rotation PR to improve robustness, prevent data loss, and fix race conditions.

String handling

• Replace replaceAll('.log', '') with endsWith() + substring() to handle edge cases like my.log.log

Race condition fix

• Made initLogger synchronous to ensure rotation completes before FileLogPrinter opens file

Data loss prevention

• Modified _compressFile to return bool indicating success
• Delete backup only if compression succeeds AND zip file exists with non-zero size
• Log warning if zip is empty

Code quality

• Replaced print with debugPrint for consistency
• Added comprehensive documentation for LogRotation class and methods
• Clarified backup sorting logic (oldest-first, delete oldest beyond limit)
• Removed unused currentPath parameter from _cleanupOldBackups

Dependencies

• Moved archive from dev_dependencies to dependencies (used in production code)

// Before: unsafe deletion
_compressFile(backupPath, zipPath);
File(backupPath).deleteSync();

// After: verified deletion
final compressionSucceeded = _compressFile(backupPath, zipPath);
if (compressionSucceeded && File(zipPath).existsSync()) {
  if (File(zipPath).lengthSync() > 0) {
    File(backupPath).deleteSync();
  }
}

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