docs: migrate LiveSync to edge2 CT 104; decommission TAK/Watchtower/echo6-agent/Nexus

- LiveSync -> edge2 CT 104 (CouchDB cold volume-tar; two-token Caddy cutover; per-user JWT)
- Decommissioned + code-archived to Forge: TAK+SIGIL, Watchtower, echo6-agent, nexus-hub, nexus-agent
- Removed tak.echo6.co + wt.echo6.co Caddy blocks, dnsmasq entries, and GoDaddy A records
- runbook: add CouchDB data variant (Variant D) + multi-token Caddy cutover example
- fix stray 'f ' artifact in environment.md

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

.obsidian/workspace.json

@@ -185,6 +185,7 @@
   },
   "active": "ea4cc678c44e8b67",
   "lastOpenFiles": [
+    "docs/hardware/environment.md.tmp.40509.b6a12d701b09",
     "docs/hardware/environment.md",
     "nodes/ots-ct.md",
     "mocs/mesh.md",
@@ -210,7 +211,6 @@
     "nodes/meshai-ct.md",
     "nodes/meshmonitor-ct.md",
     "nodes/utility.md",
-    "mocs/vault-conventions.md",
     "mocs",
     "hardware",
     "services",