[mikelangmayr]

• [paths] in instrument.toml sets etc, venv, repo and logs, each resolved as <PREFIX>_*_DIR, then the file, then the name-derived default, so a non-standard layout is recorded in the instrument's repository rather than in each operator's environment
• An instance's config path is now derived as <etc>/<instance>.yaml instead of being declared per instance, which is what made the layout only half-configurable: moving etc left the configs behind
• deploy, status --verbose, doctor and the secret scan all use the derived path; doctor warns when a deployed instance file still sets the now-unread variable
• installer.log_dir and doctor.LOG_DIR_TEMPLATE each derived /var/log/<name> separately; both now use paths.logs
• Adds instrument.toml.example, with a test that it still loads so it cannot drift from the schema
• 46 tests pass, pylint 10.00