port build_host_files.py to Go, simplify Hermes MCP, cutover final

- cmd/hermes/main.go: removed redundant /mcp endpoint — Hermes gateway now
  serves only /query + /healthz. MCP goes direct to API (:8090/mcp).
- cmd/oikos/build_hosts.go: Go port of mcp/build_host_files.py as
  'oikos build-hosts'. Reads inventory.yaml, writes hosts/*.yaml.
- cmd/oikos/main.go: added build-hosts role.
- docker-compose.yml: hermes service simplified.
- apps/105: all 6 Oikos services stopped + disabled (confirmed inactive).
- Watchdog cron installed, API stop/restart verified.
- Infisical bootstrap pending (image pull timeout — retry separately).

Remaining:
- Port bin/homelab CLI to Go (separate plan — large surface)
- Caddy DNS push (needs dtoro/caddy-conf repo access)
- Rollback drill

hosts/elementsynapse.yaml

@@ -1,31 +1,31 @@
-# Generated by mcp/build_host_files.py from inventory.yaml.
-# Do NOT edit by hand — your changes will be overwritten.
-# Source of truth: ../inventory.yaml
-name: elementsynapse
-kind: lxc
-os: linux
-role: matrix-server
-state: active
+# Generated by oikos build-hosts from inventory.yaml.
+# Do NOT edit by hand.
+
 host: strong
-pve_id: 118
+kind: lxc
 lan_ip: 192.168.8.242
+mcp_endpoint: https://mcp.hubris.network/mcp
 mesh:
   tailscale: {}
 mesh_globals:
-  primary: netbird
   accepted:
-  - netbird
-  - tailscale
-public_host: matrix.hubris.network
-runs:
-- matrix
-services_hosted:
-- name: matrix
-  url: https://matrix.hubris.network
-  backend: elementsynapse
-  doc_page: knowledge/wiki/containers/118-elementsynapse.md
-  risk_notes: "alert/approval channel for Oikos \u2014 outage silences agent escalation"
+    - netbird
+    - tailscale
+  primary: netbird
+name: elementsynapse
 notes:
-- Migrated from hubris to strong 2026-07-05 (Phase 1 of strong migration plan).
-mcp_endpoint: https://mcp.hubris.network/mcp
+  - Migrated from hubris to strong 2026-07-05 (Phase 1 of strong migration plan).
+os: linux
+public_host: matrix.hubris.network
+pve_id: 118
+role: matrix-server
+runs:
+  - matrix
 secrets_issuance_endpoint: https://secrets.hubris.network/issue
+services_hosted:
+  - backend: elementsynapse
+    doc_page: knowledge/wiki/containers/118-elementsynapse.md
+    name: matrix
+    risk_notes: alert/approval channel for Oikos — outage silences agent escalation
+    url: https://matrix.hubris.network
+state: active