Pure formatting, no behaviour change: strip trailing whitespace from blank
lines, give top-level defs in system_cacher.py their two blank lines, wrap
the long discord_radio.join signature, and split the duplicated
active_config ternary in main.py and routers/api.py across lines.
Verified clean with flake8 --max-line-length=120, matching CI.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>