warpgate-ssh: remote Linux/macOS terminals through the relay; oregon launched remotely

The dispatcher moves to an LXC without agent CLIs (design 9), so every terminal is
reached through Warpgate. The relay call (agent-access.py run --target <t>) lives in
one helper; the target comes from the terminal config.

os linux/darwin (PosixWarpgateTransport): each primitive is one bash -c call. Files
go up as base64 (chunked above 60k), start_run stages prompt.md + run.sh and launches
in a single round trip; the runner is detached with setsid nohup (pid == pgid == sid,
$! kept in launch.pid); kill signals the process group and session (TERM, then KILL),
skipped once exit.txt exists. macOS detaches with perl POSIX::setsid.

os windows keeps the win10-ps.sh / win10-put.sh helper scripts (target win10) and
schtasks, now through the shared call() helper.

oregon is now warpgate-ssh (target oregon, run_root ~/.gwent-board/agentd-runs);
the local transport stays for co-located setups and tests.

config/agentd.yaml

@@ -5,7 +5,7 @@ vault: {client: ~/.local/share/server-access-client/agent-access.py, config: htt
 
 agentd:
   state_dir: ~/.gwent-board/agentd     # JSON state, agentd.log, heartbeat.json, local run dirs (runs/)
-  helpers_dir: /home/ubuntu/Documents/wjj/project/gwent-design/tools   # win10-ps.sh / win10-put.sh
+  helpers_dir: /home/ubuntu/Documents/wjj/project/gwent-design/tools   # win10-ps.sh / win10-put.sh (Windows terminals only)
   interval: 120
   max_rounds_per_thread: 8
   comment_max_chars: 6000
@@ -27,14 +27,19 @@ terminals:
     capabilities: [android, game]
     executors: [codex]
   oregon:
-    transport: local
+    # remote even though agentd runs on oregon today: the dispatcher is moving to an LXC without agent CLIs
+    # (design §9), so this goes through Warpgate like any other host. `transport: local` + `launch: subprocess`
+    # still works for a dispatcher co-located with its executors.
+    transport: warpgate-ssh
+    target: oregon                      # agent-access.py target name
     os: linux
-    launch: subprocess
+    launch: nohup
     repo: /home/ubuntu/Documents/wjj/project/gwent
+    run_root: /home/ubuntu/.gwent-board/agentd-runs   # absolute: the remote shell does not expand ~ inside quotes
     plane_user: oregon
     token_key: PLANE_OREGON_API_TOKEN
     concurrency: 1                      # one shared worktree: no parallel edits
-    bins: {claude: /home/ubuntu/.local/bin/claude}   # cron has a minimal PATH; codex is not installed on oregon
+    bins: {claude: /home/ubuntu/.local/bin/claude}   # the SSH non-login shell has the system PATH only; no codex on oregon
     executors: [claude-code]
 
 executors: