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>

test-features.mjs

@@ -1691,6 +1691,52 @@ test("buildTuiCmd keeps version pin + entrypoint label + MCP wall", () => {
   assert.ok(/-u CLAUDE_CODE_ENTRYPOINT/.test(auto), "auto mode unsets any inherited entrypoint");
 });
 
+// CLAUDE_CODE_OAUTH_TOKEN passthrough (PI231 401 incident): tmux doesn't forward the parent
+// env to the pane, so the token must be set explicitly on the pane command or the TUI claude
+// falls back to credentials.json (whose refresh token gets corrupted by the spawn/kill cycle).
+test("buildTuiCmd passes CLAUDE_CODE_OAUTH_TOKEN when the env is set (shq-escaped)", () => {
+  const save = process.env.CLAUDE_CODE_OAUTH_TOKEN;
+  try {
+    process.env.CLAUDE_CODE_OAUTH_TOKEN = "sk-ant-oat01-abc123";
+    const cmd = buildTuiCmd("/usr/bin/claude", "m", "sid-tok", "/home/u", "cli");
+    // shq wraps in single quotes; a plain token renders as 'token'.
+    assert.ok(cmd.includes("CLAUDE_CODE_OAUTH_TOKEN='sk-ant-oat01-abc123'"),
+      "token must be set on the pane command, shq-escaped");
+  } finally {
+    if (save === undefined) delete process.env.CLAUDE_CODE_OAUTH_TOKEN;
+    else process.env.CLAUDE_CODE_OAUTH_TOKEN = save;
+  }
+});
+
+test("buildTuiCmd does NOT add CLAUDE_CODE_OAUTH_TOKEN when the env is unset", () => {
+  const save = process.env.CLAUDE_CODE_OAUTH_TOKEN;
+  try {
+    delete process.env.CLAUDE_CODE_OAUTH_TOKEN;
+    const cmd = buildTuiCmd("/usr/bin/claude", "m", "sid-notok", "/home/u", "cli");
+    assert.ok(!/CLAUDE_CODE_OAUTH_TOKEN/.test(cmd),
+      "no token added when env unset (credentials.json-only hosts unaffected)");
+  } finally {
+    if (save === undefined) delete process.env.CLAUDE_CODE_OAUTH_TOKEN;
+    else process.env.CLAUDE_CODE_OAUTH_TOKEN = save;
+  }
+});
+
+test("buildTuiCmd shq-escapes a token containing shell metacharacters (no injection)", () => {
+  const save = process.env.CLAUDE_CODE_OAUTH_TOKEN;
+  try {
+    // A token with a single quote must be escaped via the '\'' idiom so it can't break out
+    // of the shell string tmux runs via sh -c.
+    process.env.CLAUDE_CODE_OAUTH_TOKEN = "tok'; rm -rf /;'";
+    const cmd = buildTuiCmd("/usr/bin/claude", "m", "sid-inj", "/home/u", "cli");
+    assert.ok(cmd.includes(`CLAUDE_CODE_OAUTH_TOKEN='tok'\\''; rm -rf /;'\\'''`),
+      "single quote must be shq-escaped, not left bare");
+    assert.ok(!/CLAUDE_CODE_OAUTH_TOKEN=tok'; rm/.test(cmd), "raw unescaped token must NOT appear");
+  } finally {
+    if (save === undefined) delete process.env.CLAUDE_CODE_OAUTH_TOKEN;
+    else process.env.CLAUDE_CODE_OAUTH_TOKEN = save;
+  }
+});
+
 test("buildTuiCmd OCP_TUI_FULL_TOOLS=1 grants -p-equivalent tool surface (single-user opt-in)", () => {
   const save = { ...process.env };
   const restore = () => {
@@ -1766,6 +1812,41 @@ test("reaper returns 0 for empty session list", () => {
   assert.equal(killed.length, 0);
 });
 
+// Defunct-zombie reaping (PI231 incident): the pane's claude is a child of the tmux server,
+// so only kill-server actually reaps it. We kill-server ONLY when no foreign session remains.
+console.log("\nTUI defunct-zombie reaping (kill-server):");
+
+test("reaper kill-servers when the server is ours-only (flush defunct claude zombies)", () => {
+  const calls = [];
+  const fakeTmux = (args) => {
+    calls.push(args.join(" "));
+    if (args[0] === "list-sessions") return { status: 0, stdout: "ocp-tui-aaaa\nocp-tui-bbbb\n" };
+    return { status: 0, stdout: "" };
+  };
+  const n = reapStaleTuiSessions({ tmux: fakeTmux });
+  assert.equal(n, 2, "killed both of our sessions");
+  assert.ok(calls.includes("kill-server"), "kill-server fired — reaps the defunct backlog");
+});
+
+test("reaper does NOT kill-server when a foreign (non-ocp) session remains (coexistence)", () => {
+  const calls = [];
+  const fakeTmux = (args) => {
+    calls.push(args.join(" "));
+    if (args[0] === "list-sessions") return { status: 0, stdout: "ocp-tui-aaaa\nolp-tui-bbbb\n" };
+    return { status: 0, stdout: "" };
+  };
+  const n = reapStaleTuiSessions({ tmux: fakeTmux });
+  assert.equal(n, 1, "killed only our own session");
+  assert.ok(!calls.includes("kill-server"), "kill-server MUST NOT fire — would disrupt olp-tui-*");
+});
+
+test("reaper does NOT kill-server when there is no server (status !== 0)", () => {
+  const calls = [];
+  const fakeTmux = (args) => { calls.push(args.join(" ")); return { status: 1, stdout: "" }; };
+  reapStaleTuiSessions({ tmux: fakeTmux });
+  assert.ok(!calls.includes("kill-server"), "no server → no kill-server (early return)");
+});
+
 // ── TUI home preparation (scratch vs real) ───────────────────────────────
 import { prepareTuiHome, ensureTuiCwdTrusted } from "./lib/tui/session.mjs";
 import { mkdtempSync as hMkdtemp, mkdirSync as hMkdir, writeFileSync as hWrite, readFileSync as hRead, existsSync as hExists, readlinkSync as hReadlink } from "node:fs";