#2122 gitignore: local per-machine root files

Beschreibung

Root-anchored ignores for local client configs, launch helpers and server logs (*.out, claude-*.sh, mode-*.sh, mcp.*.json, opencode.work.jsonc), so they never block update.sh's git pull --ff-only. Opt-in, default path untouched; committed bench/results/**/*.out stay tracked.