logs.dir in the User config #112

Parent

#109

What to build

A [logs] dir setting in the User config sets where session logs are written, defaulting to ~/.thirdshift/logs as today. The log filename scheme doesn't change.

• A leading ~ is expanded to $HOME.
• A relative path is rejected with a clear error before any work, because the directory the Run is launched from is not a meaningful base.

The "session log:" line a Failed run prints points into the configured directory. The README documents logs.dir.

Acceptance criteria

• With no logs.dir, session logs are still written to ~/.thirdshift/logs
• With logs.dir = "~/elsewhere/logs", session logs are written under $HOME/elsewhere/logs (created if missing)
• With an absolute logs.dir, session logs are written there
• A relative logs.dir stops the Run before any work, with an error naming the setting
• A Failed run's "session log:" line shows the path under the configured directory
• README documents logs.dir

Blocked by

• User config, with merge.always and --no-merge #111