docs(deploy): cochi redeploy guide + deploy skill

plan/14-deploy.md: git pull main + hard restart (compose down ->
build-stack.sh --up online), drasl/online, verify + rollback.
.claude/skills/deploy: skill to run it (pre-check, pull, hard restart,
verify) with prod guardrails.

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

.claude/skills/deploy/SKILL.md

@@ -0,0 +1,66 @@
+---
+name: deploy
+description: Redeploy the Ulicraft Minecraft stack to the production host `cochi` — git pull on main then a hard restart (compose down + build-stack.sh --up online). Use when the user says "deploy", "redeploy", "deploy to cochi", "push to prod", "ship it", or "restart the server" for this project. Causes brief Minecraft downtime.
+---
+
+# Deploy Ulicraft to `cochi`
+
+Redeploy the running stack on the production host. Full reference:
+`plan/14-deploy.md`.
+
+## Fixed parameters
+
+- Host: `cochi` (SSH alias)
+- Path: `/home/ubuntu/mc/ulicraft-server-v1`
+- Branch: `main`
+- Run mode: `online` → compose files `docker-compose.yml` + `docker-compose.static.yml`
+- Auth: Drasl (base stack)
+- Restart: **hard** (down → up) — players are disconnected for a few minutes
+
+## Procedure
+
+This is an outward-facing, downtime-causing action on production. The user
+invoking this skill is the authorization to proceed, but:
+
+1. **Pre-check (read-only).** See what would change before tearing anything down:
+   ```bash
+   ssh cochi 'cd /home/ubuntu/mc/ulicraft-server-v1 && git fetch && git log --oneline HEAD..@{u}'
+   ```
+   Report the incoming commits. If the list is empty, tell the user the host is
+   already up to date and ask whether to restart anyway (they may want a plain
+   restart). If `git fetch` fails (host unreachable, auth), STOP and report.
+
+2. **Pull + hard restart** (single SSH session, halts on any error):
+   ```bash
+   ssh cochi 'set -e
+     cd /home/ubuntu/mc/ulicraft-server-v1
+     git pull --ff-only
+     docker compose -f docker-compose.yml -f docker-compose.static.yml down --remove-orphans
+     tooling/build-stack.sh --up online'
+   ```
+   - `--ff-only` refuses to merge — if the pull is not a fast-forward, STOP and
+     report (local changes on the host need manual resolution).
+   - `build-stack.sh --up online` renders configs (needs `.env` complete:
+     `BASE_DOMAIN`, `HOST_LAN_IP`, `RCON_PASSWORD`) and runs `compose up -d`.
+
+3. **Verify.**
+   ```bash
+   ssh cochi 'cd /home/ubuntu/mc/ulicraft-server-v1 && docker compose -f docker-compose.yml -f docker-compose.static.yml ps'
+   ```
+   Confirm `caddy`, `drasl`, `minecraft`, `mc-backup` are Up. Tail the minecraft
+   log briefly and confirm it reaches `Done` (server ready):
+   ```bash
+   ssh cochi 'cd /home/ubuntu/mc/ulicraft-server-v1 && timeout 120 docker compose -f docker-compose.yml -f docker-compose.static.yml logs -f minecraft' 2>/dev/null | grep -m1 "Done"
+   ```
+
+## Guardrails
+
+- Never `git reset --hard` or discard changes on `cochi` without telling the user
+  first — there may be host-local edits.
+- Volumes (`mc_data`, `drasl_state`) persist across `down`; the world is safe. Do
+  NOT pass `-v`/`--volumes` to `down`.
+- If a step fails, STOP and surface the exact error + the failing command. Do not
+  improvise recovery on production.
+- Blessing Skin variant or `airgap` mode changes the compose file set — if the
+  user asks for those, follow `plan/14-deploy.md` instead of the fixed commands
+  above.