feat: add configurable log splitting for run.log

[Copilot]

What problem does this PR solve?

Problem Summary:

ckb run writes continuously to data/logs/run.log, which can become very large during long-running sync and slow down incident-time troubleshooting. Operators need an opt-in way to split logs by time window while keeping current behavior by default.

What is changed and how it works?

What's Changed:

• Logger config
  • Adds logger.log_file_split with supported values:
    • "never": current single-file behavior
    • "hourly": one main log file per UTC hour
    • "daily": one main log file per UTC day

[logger]
log_file_split = "hourly"

• Log file naming

  • Hourly files use: run.YYYY-MM-DD-HH.log
  • Daily files use: run.YYYY-MM-DD.log
  • Example: data/logs/run.2026-03-10-20.log

• Runtime behavior

  • Default remains run.log.
  • Time-windowed files are selected using the log record timestamp.
  • Extra loggers are unchanged.

• Config template

  • Documents log_file_split in generated ckb.toml.

Related changes

• PR to update owner/repo:
• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test

Side effects

• No breaking backward compatibility