Plane client, transports and executor adapters

Plane: paginated issue/comment/state/label/member access, one client per
terminal identity. Transports: local (setsid-detached runner) and warpgate-ssh
(win10-ps.sh / win10-put.sh relay, schtasks launch, taskkill on timeout).
Executors share a runner shape (prompt.md, exit.txt marker) with codex,
claude-code and shell adapters for last message and thread id.

agentd/executors/codex.py

@@ -0,0 +1,23 @@
+"""Codex CLI: `codex exec --json ... -o last.md -` (stdin prompt), resume with `codex exec resume <thread>`.
+Thread id comes from the `thread.started` event in events.jsonl; the last message from last.md."""
+import json
+
+from .base import ExecResult, RunnerExecutor
+
+
+class CodexExecutor(RunnerExecutor):
+    stdout_name = "events.jsonl"
+
+    def collect(self, handle):
+        t, d = self.transport, handle["run_dir"]
+        last = t.read_text(t.join(d, "last.md")) or ""
+        thread = handle.get("thread_id")
+        line = t.grep_first(t.join(d, "events.jsonl"), "thread.started")
+        if line:
+            try:
+                thread = json.loads(line).get("thread_id") or thread
+            except ValueError:
+                pass
+        tail = (self.stderr_tail(handle) + "\n" + t.tail(t.join(d, "events.jsonl"), 1)[-600:]).strip()
+        return ExecResult(last.strip(), self.exit_code(handle), thread,
+                          self.logs(handle, "events.jsonl", "stderr.txt", "last.md"), tail)