docs: onboard AdGuard Home to Ansible; retire check-mx2; migrate plan to Linear

- Add dns.windy.lan to Ansible inventory (adguardhome group/profile) with a
  read-only healthcheck template, systemd timer, and on-demand report parity
  with the other active hosts; verified green on the host.
- Add synapse.chans.xyz to the AGENTS.md active-host quick map.
- Remove plans/; migrate decisions/verification to a Linear vps project doc and
  file the remaining gaps as W1N-46..49 with blocking edges.
- Retire scripts/check-mx2.sh; point mailcow health/update runbooks and the
  mx2 host file at the Ansible health report.
- Trim us2 stub software to verified running services; note dormant dirs.
- Normalize repo docs to English; drop the non-existent CONTEXT.md/ADR claim
  and remove docs/agents/domain.md.

AGENTS.md

@@ -27,6 +27,8 @@ Also readable as `agent.md` (symlink → this file).
 | **mx2.windy.me** | mailcow (`/opt/mail`, project `cow`) | `ssh -4 windy@mx2.windy.me` | [hosts/mx2.windy.me.md](hosts/mx2.windy.me.md) |
 | **us2.wsvc.info** | Vaultwarden + Traefik (+ Soft Serve, …) | `ssh -4 windy@us2.wsvc.info` | [hosts/us2.wsvc.info.md](hosts/us2.wsvc.info.md) |
 | **hk2.chans.xyz** | PowerDNS auth ns1 (`/opt/pdns`) | `ssh -4 windy@hk2.chans.xyz` | [hosts/hk2.chans.xyz.md](hosts/hk2.chans.xyz.md) |
+| **synapse.chans.xyz** | Matrix ESS (Synapse + MAS + Element) on K3s | `ssh -4 windy@synapse.chans.xyz` | [hosts/synapse.chans.xyz.md](hosts/synapse.chans.xyz.md) |
+| **dns.windy.lan** | AdGuard Home LAN DNS + Mihomo explicit proxy | `ssh -4 windy@192.168.66.36` | [hosts/dns.windy.lan.md](hosts/dns.windy.lan.md) |
 | **gfw.windy.lan** | OpenWrt LAN gateway / OpenClash | `ssh -4 root@192.168.66.1` | [hosts/gfw.windy.lan.md](hosts/gfw.windy.lan.md) |
 | **gw** | EdgeRouter X primary LAN gateway | `ssh -4 zhiqiang@192.168.66.254` | [hosts/gw.md](hosts/gw.md) |
 | **ubnt** | UniFi Network Controller | `ssh -4 windy@192.168.66.46` | [hosts/ubnt.md](hosts/ubnt.md) |
@@ -60,7 +62,7 @@ Also readable as `agent.md` (symlink → this file).
 
 | Task | Path |
 |------|------|
-| mailcow health | [runbooks/mailcow-health.md](runbooks/mailcow-health.md) · `./scripts/check-mx2.sh` |
+| mailcow health | [runbooks/mailcow-health.md](runbooks/mailcow-health.md) |
 | mailcow update | [runbooks/mailcow-update.md](runbooks/mailcow-update.md) |
 | mailcow SMTP/IMAP client | [runbooks/mailcow-smtp-client.md](runbooks/mailcow-smtp-client.md) |
 | Vaultwarden health | [runbooks/vaultwarden-health.md](runbooks/vaultwarden-health.md) |
@@ -69,16 +71,23 @@ Also readable as `agent.md` (symlink → this file).
 | PowerDNS health (hk2) | [runbooks/pdns-health.md](runbooks/pdns-health.md) |
 | PowerDNS upstream refs | [docs/pdns-upstream.md](docs/pdns-upstream.md) |
 | Matrix health | [runbooks/matrix-health.md](runbooks/matrix-health.md) |
+| AdGuard Home health | [runbooks/adguard-home-health.md](runbooks/adguard-home-health.md) |
 | Matrix upstream refs | [docs/matrix-upstream.md](docs/matrix-upstream.md) |
 | Hermes Agent Matrix channel | [docs/hermes-matrix.md](docs/hermes-matrix.md) |
 | UniFi local-service proxy bypass | [docs/unifi-openclash-localhost.md](docs/unifi-openclash-localhost.md) |
 | Routine Ansible operations | [runbooks/ansible-operations.md](runbooks/ansible-operations.md) |
 
-```bash
-./scripts/check-mx2.sh
-```
+Routine mailcow health: `cd ansible && ansible-playbook playbooks/health-report.yml --limit mailcow`. The local stub resolver is flaky; DNS probes use `1.1.1.1` / `8.8.8.8`.
 
-`check-mx2.sh` defaults to IPv4; set `MX2_ALLOW_IPV6=1` to allow IPv6. DNS checks use `1.1.1.1` / `8.8.8.8` (local stub is flaky).
+## Agent skills
+
+### Issue tracker
+
+Issues are tracked in Linear and created/updated via the Linear MCP (`vps` project). See `docs/agents/issue-tracker.md`.
+
+### Triage labels
+
+Default triage labels: needs-triage, needs-info, ready-for-agent, ready-for-human, wontfix. See `docs/agents/triage-labels.md`.
 
 ## Safety
 
@@ -116,5 +125,4 @@ inventory/hosts.md     # machine index
 hosts/                 # per-host facts
 runbooks/              # step-by-step ops
 docs/                  # upstream doc indexes / design notes
-scripts/               # read-only helper scripts
 ```