Parent
Part of #414
Problem
sandbox_stderr_pipe rebuilds carry via toString() + split('\\n') on each chunk. A plugin emitting a huge line without newline → O(n²) copies + heavy sanitize regexes.
Evidence
lib/core/extensions/sandbox/sandbox_stderr_pipe.dart
lib/core/extensions/sandbox/sandbox_sanitizer.dart
Acceptance
Suggested fix
Cap carry; scan for newlines incrementally; bound sanitize input.
Parent
Part of #414
Problem
sandbox_stderr_piperebuilds carry viatoString()+split('\\n')on each chunk. A plugin emitting a huge line without newline → O(n²) copies + heavy sanitize regexes.Evidence
lib/core/extensions/sandbox/sandbox_stderr_pipe.dartlib/core/extensions/sandbox/sandbox_sanitizer.dartAcceptance
Suggested fix
Cap carry; scan for newlines incrementally; bound sanitize input.