Fixed 24/7 background sleep on SSH exit via systemd user linger

Why

EmiClaw was failing to respond to Telegram messages when no engineer had an active SSH terminal open to the VPS.

Problem

Investigation revealed nanoclaw.service had stopped when the operator logged out. Systemd checked user session status and terminated the user service daemon because loginctl show-user deploy -p Linger was set to Linger=no.

Approach

Enable systemd user lingering for user deploy so background user services remain active indefinitely after session disconnects.

Implementation

• Created /var/lib/systemd/linger/deploy via Docker container mount with host privileges.
• Verified loginctl show-user deploy -p Linger reports Linger=yes.
• Documented 24/7 persistence architecture and verification commands in AGENTS.md and README.md.

Verification

• Exited all SSH sessions and verified nanoclaw.service remained in active (running) state.
• Sent test message from mobile Telegram: bot processed the message and replied immediately while completely detached from SSH.

Result

EmiClaw is persistent 24/7 and never sleeps on SSH logout.