[codex] Use rolling files for Windows sandbox logs

[iceweasel-oai]

Why

Windows sandbox diagnostics currently append to a single sandbox.log under CODEX_HOME/.sandbox. That file never rolls over, which makes it hard to safely include sandbox diagnostics in future feedback reports without risking unbounded growth.

What changed

• Replaced direct append-open sandbox logging with tracing_appender::rolling::RollingFileAppender.
• Configured sandbox logs to rotate daily using names like sandbox.YYYY-MM-DD.log.
• Added a conservative MAX_LOG_FILES cap of 90 retained matching log files.
• Routed the Windows sandbox setup helper through the same rolling writer.
• Added helpers for resolving the current daily sandbox log path so future feedback upload work can use the same filename logic.
• Updated tests and test diagnostics to read the dated daily log file.

This intentionally does not include sandbox logs in /feedback yet; scrubbing and attachment behavior can happen in a follow-up.

Testing

• cargo fmt -p codex-windows-sandbox
• cargo check -p codex-windows-sandbox
• cargo test -p codex-windows-sandbox
• cargo test -p codex-windows-sandbox logging::tests
• cargo clippy -p codex-windows-sandbox --all-targets -- -D warnings

[zm-oai]

ship it