feat: run dream cycle as a systemd user service + journald-visible logs

- deploy/lyra-dream.service: --loop 1800 user service on lyra-cortex, so Lyra's
  consolidation + reflection keeps ticking unattended between conversations
- deploy/README.md: install / linger / operate runbook
- logbus: mirror events to stderr so out-of-band runs (the dream service under
  journald) are observable, not just via the in-process web SSE feed

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

deploy/README.md

@@ -0,0 +1,39 @@
+# Deploy
+
+## Dream cycle (`lyra-dream.service`)
+
+Lyra's unattended inner loop. Runs `lyra-dream --loop 1800` so she consolidates
+memory and reflects every 30 min between conversations. Installed as a
+**systemd user service** on `lyra-cortex` (10.0.0.41), running as `serversdown`
+— no root needed to manage it.
+
+### Install / update
+
+```bash
+cp deploy/lyra-dream.service ~/.config/systemd/user/lyra-dream.service
+systemctl --user daemon-reload
+systemctl --user enable --now lyra-dream.service
+```
+
+### Persist across reboot / logout (one-time, needs sudo)
+
+A user service stops when the user logs out and doesn't start at boot until
+login — unless lingering is enabled:
+
+```bash
+sudo loginctl enable-linger serversdown
+```
+
+### Operate
+
+```bash
+systemctl --user status lyra-dream.service      # is she ticking?
+journalctl --user -u lyra-dream.service -f       # watch her think (logbus -> stderr)
+systemctl --user restart lyra-dream.service      # after a code change
+systemctl --user stop lyra-dream.service         # quiet her down
+```
+
+Tunables live in `lyra/dream.py` (drive thresholds, curiosity gains) and the
+`--loop` interval in the unit's `ExecStart`. The consolidation backend follows
+`SUMMARY_BACKEND` in `.env` (cloud gpt-4o-mini for bulk; the MI50 is too slow
+for the summarization backfill).