fix(tui): pass CLAUDE_CODE_OAUTH_TOKEN to spawned claude + reap defunct sessions

Root cause (PI231 incident): tmux does not forward the parent's env to the
pane, so the TUI claude never saw CLAUDE_CODE_OAUTH_TOKEN and fell back to
~/.claude/.credentials.json, whose single-use refresh token got corrupted to an
empty string by the per-request spawn + kill-session teardown racing claude's
token rotation -> permanent "Please run /login" 401 (re-login re-corrupted on
the next spawn). Connected leak: the pane's claude is a child of the tmux server
(not node), so kill-session left <defunct> zombies the server never reaped (25
over 30 days; tmux kill-server dropped it 25->3).

Fix 1: buildTuiCmd now adds CLAUDE_CODE_OAUTH_TOKEN=<shq-escaped> to the pane
env prefix when the env is set, so claude authenticates via the long-lived token
and never touches the credentials.json refresh path (matching stable hosts).
Unset -> no token added (credentials.json-only hosts unaffected).

Fix 2: reapStaleTuiSessions kill-servers after clearing our own sessions ONLY
when no foreign tmux session remains (never disrupts a co-hosted olp-tui-*).
kill-server is the only node-reachable action that ACTUALLY reaps -- server exit
reparents survivors to init, which waitpids them; a per-session kill cannot,
since node is not the zombies' parent. Added a 15-min periodic reap (server.mjs)
gated on TUI_MODE and on the TUI path being idle. Residual: a request whose pane
is created in the idle-check/kill-server window fails cleanly via the existing
honesty gates (documented).

ALIGNMENT: Class B (OCP-owned TUI spawn). cli.js does NOT perform either
operation -- there is no cli.js analogue for "how the TUI pane authenticates" or
"reaping tmux-server-owned zombies"; authorized by ADR 0007 (PR-C amendment) per
ALIGNMENT.md's Class B citation requirement. No Class A wire surface, no endpoint
shape, no alignment.yml token, and no models.json entry touched.

Tests: +6 in test-features.mjs (buildTuiCmd token set/unset/shq-injection;
reaper kill-server ours-only / foreign-present / no-server). 241 passed, 0 failed.

Co-Authored-By: Claude <claude-opus> <noreply@anthropic.com>

lib/tui/session.mjs

@@ -23,16 +23,44 @@ const defaultTmux = (args, opts = {}) =>
 
 // Kill ONLY our own stale sessions. Scoped to SESSION_PREFIX so a co-hosted
 // OLP test instance's `olp-tui-*` sessions are never touched.
+//
+// Defunct-reaping (PI231 incident): the pane's `claude` process is a child of the
+// long-lived tmux SERVER daemon, NOT of the OCP node process — `tmux new-session -d`
+// returns the instant the server forks the pane, so node never becomes its parent and
+// therefore can NEVER waitpid()/reap it (a SIGKILL still needs the *parent* to reap, and
+// here that parent is the tmux server). `kill-session` destroys the session but the server
+// can leave the pane's `claude` (and any grandchildren claude spawned) as `<defunct>`
+// zombies that only the server can reap. Over many per-request spawn+teardown cycles these
+// accumulate (live evidence on PI231: 25 defunct `<claude>` over 30 days; `tmux kill-server`
+// dropped it 25→3). The only node-reachable action that ACTUALLY reaps them — rather than
+// merely re-signalling — is to stop the tmux server: when the server exits, the kernel
+// reparents its surviving children to init (PID 1), which reaps them immediately.
+//
+// So after killing our own sessions, if the server has NO sessions left of ANY prefix
+// (i.e. nothing we could disrupt — no co-hosted `olp-tui-*` or other instance), we
+// `kill-server` to flush the defunct backlog. If ANY non-ocp session remains we leave the
+// server running (coexistence rule, ADR 0007) and let the next boot/periodic sweep retry
+// once the server is otherwise idle.
 export function reapStaleTuiSessions({ tmux = defaultTmux } = {}) {
   const r = tmux(["list-sessions", "-F", "#{session_name}"]);
   if (!r || r.status !== 0) return 0; // no tmux server / no sessions
+  const names = String(r.stdout || "").split("\n").map((s) => s.trim()).filter(Boolean);
   let killed = 0;
-  for (const name of String(r.stdout || "").split("\n").map((s) => s.trim()).filter(Boolean)) {
+  let othersRemain = false;
+  for (const name of names) {
     if (name.startsWith(SESSION_PREFIX)) {
       tmux(["kill-session", "-t", name]);
       killed++;
+    } else {
+      othersRemain = true; // a session we do NOT own (e.g. olp-tui-*) — never kill-server
     }
   }
+  // Reap defunct `claude` zombies: safe ONLY when the server is now ours-only/empty.
+  // kill-server is what actually reaps (server exit reparents survivors to init); a
+  // per-session kill cannot, since node is not the zombies' parent.
+  if (!othersRemain) {
+    tmux(["kill-server"]);
+  }
   return killed;
 }
 
@@ -217,6 +245,27 @@ export function buildTuiCmd(claudeBin, model, sessionId, ehome, entrypointMode)
     "CLAUDE_CODE_DISABLE_CLAUDE_MDS=1",
     "CLAUDE_CODE_DISABLE_AUTO_MEMORY=1",
   ];
+  // CLAUDE_CODE_OAUTH_TOKEN: tmux does NOT forward the parent process's env to the pane (the
+  // same reason the whole env is delivered as an `env` prefix above — verified live 2026-06-01),
+  // so the token MUST be set explicitly here or the spawned `claude` never sees it. Without it,
+  // the TUI claude falls back to authenticating via <HOME>/.claude/.credentials.json, whose
+  // single-use refresh token gets corrupted by the per-request spawn + `kill-session` teardown
+  // racing claude's token-rotation write (the PI231 incident: refresh token ended up an empty
+  // string → permanent 401 "Please run /login", re-login re-corrupted on the next spawn). With
+  // the long-lived OAuth token in env, claude authenticates via the token and never touches the
+  // credentials.json refresh path — matching how the stable oracle / Mac-mini hosts already run.
+  //
+  // SECURITY: the token appears in the pane command (ps-visible). This is acceptable for the
+  // single-user A-path — it mirrors the existing plaintext-token practice (server.mjs reads the
+  // same CLAUDE_CODE_OAUTH_TOKEN env at getOAuthCredentials()), and the multi-user B-path is
+  // already refused at boot (TUI + AUTH_MODE=multi is a hard FATAL). Read from process.env here,
+  // consistent with how buildTuiCmd already reads OCP_TUI_FULL_TOOLS / CLAUDE_ALLOWED_TOOLS below.
+  //
+  // When the env is unset (e.g. a host that intentionally relies on credentials.json), no token
+  // is added — behaviour is byte-for-byte unchanged from before this fix.
+  if (process.env.CLAUDE_CODE_OAUTH_TOKEN) {
+    sets.push(`CLAUDE_CODE_OAUTH_TOKEN=${shq(process.env.CLAUDE_CODE_OAUTH_TOKEN)}`);
+  }
   const unset = ["CLAUDECODE", "ANTHROPIC_API_KEY", "ANTHROPIC_BASE_URL", "ANTHROPIC_AUTH_TOKEN"];
   if (entrypointMode === "cli") sets.push("CLAUDE_CODE_ENTRYPOINT=cli");
   else if (entrypointMode === "auto") unset.push("CLAUDE_CODE_ENTRYPOINT"); // let claude self-classify via TTY