Greptile Summary

This PR adds two actionable recovery hints to the non-WSL systemd-unavailable error path, specifically targeting headless/SSH server users who previously only saw the generic "install/enable systemd" message. The changes are minimal and well-scoped.

• Adds loginctl enable-linger hint to persist the systemd user session across logins on headless servers
• Adds export XDG_RUNTIME_DIR=/run/user/$(id -u) hint for environments where the runtime directory is not set by PAM (common in SSH-only sessions)
• Snapshot test is correctly updated to match the expanded hint array
• Both hints are technically accurate Linux advice and are clearly labeled with context ("On a headless server...") so they do not confuse desktop or container users who also see the message

Confidence Score: 5/5

• Safe to merge — purely additive change to a string array with a matching test update, no logic or behavior regressions possible.
• The change touches only user-facing hint strings in a single function branch and its snapshot test. Both new hints are technically correct Linux advice. No branching logic, no data handling, and no external dependencies are modified. The test is properly updated and passes.
• No files require special attention.

_{Reviews (1): Last reviewed commit: "fix(daemon): add headless server hints t..." | Re-trigger Greptile}

Landed via temp rebase onto main.

• Gate: pnpm check && pnpm build && pnpm test
• Land commit: a424103
• Merge commit: 762fed1

Thanks @chocobo9!