cc-ci host on the OpenCode Go subscription key (opencode-go), not ZEN

The operator's AUTONOMIC_OPENCODE_KEY is a Go subscription key. Put in the
`opencode` (ZEN) slot it authenticates but every request fails "Insufficient
balance", because ZEN is pay-as-you-go credit; on the `opencode-go` endpoint
the same key answers fine. So the orchestrator agent moves to
opencode-go/glm-5.2, and README records that this host is a Go host and that
its opencode config must carry no inline apiKey.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FqkQq3CDmFWcQ7u1LzoyRz

cc-ci-plan/agents.toml

@@ -53,8 +53,8 @@ log_dir = "/srv/cc-ci/.cc-ci-logs"
 [[agent]]
 name    = "orchestrator"       # tmux session: cc-ci-orchestrator
 kind    = "persistent"
-backend = "opencode"           # operator 2026-09-07 (evening): NO Claude on the cc-ci host — the
-model   = "opencode/glm-5.2"   # orchestrator is an opencode agent, steered via the opencode web UI
+backend = "opencode"              # operator 2026-09-07 (evening): NO Claude on the cc-ci host — the
+model   = "opencode-go/glm-5.2"   # orchestrator is an opencode agent, steered via the opencode web UI
                                # (https://oc.ci.commoninternet.net). Claude sessions live on notplants-orchestrator.
 resume  = false                # opencode backend has no --resume equivalent (fresh session each launch)
 watch   = "heal"               # restart if dead / FATAL / backend-mismatch; never stall-reboot