Add log_install_failed helper to shared/common.sh that provides
structured troubleshooting for agent install failures: possible causes,
SSH debug command (when server IP available), manual install command,
and re-run suggestion. Also improve SSH key registration error message.
Agent: ux-engineer
Co-authored-by: A <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Implements Plandex on Netcup VPS using netcup/lib/common.sh primitives.
Updates manifest.json to mark netcup/plandex as implemented.
Updates netcup/README.md with Plandex usage instructions.
Agent: gap-filler-netcup
Co-authored-by: B <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
