fix: isolate session and plugin-data env vars in tests

Three tests fail when CODEX_COMPANION_SESSION_ID is set in the
environment (e.g., inside a Claude Code session). The session filter
drops all test jobs because they lack a sessionId field. Similarly,
the resolveStateDir tmpdir test fails when CLAUDE_PLUGIN_DATA is set.

Strip CODEX_COMPANION_SESSION_ID from the subprocess env for tests
that don't exercise session filtering, and isolate CLAUDE_PLUGIN_DATA
in the state directory test.

Fixes 4 pre-existing test failures that appear when running tests
inside a Claude Code session.

Author: tmchow

tests/runtime.test.mjs

@@ -750,8 +750,11 @@ test("status shows phases, hints, and the latest finished job", () => {
     "utf8"
   );
 
+  const env = { ...process.env };
+  delete env.CODEX_COMPANION_SESSION_ID;
   const result = run("node", [SCRIPT, "status"], {
-    cwd: workspace
+    cwd: workspace,
+    env
   });
 
   assert.equal(result.status, 0, result.stderr);
@@ -894,8 +897,11 @@ test("status preserves adversarial review kind labels", () => {
     "utf8"
   );
 
+  const env = { ...process.env };
+  delete env.CODEX_COMPANION_SESSION_ID;
   const result = run("node", [SCRIPT, "status"], {
-    cwd: workspace
+    cwd: workspace,
+    env
   });
 
   assert.equal(result.status, 0, result.stderr);
@@ -1017,8 +1023,11 @@ test("result returns the stored output for the latest finished job by default",
     "utf8"
   );
 
+  const env = { ...process.env };
+  delete env.CODEX_COMPANION_SESSION_ID;
   const result = run("node", [SCRIPT, "result"], {
-    cwd: workspace
+    cwd: workspace,
+    env
   });
 
   assert.equal(result.status, 0, result.stderr);

tests/state.test.mjs

@@ -9,11 +9,22 @@ import { resolveJobFile, resolveJobLogFile, resolveStateDir, resolveStateFile, s
 
 test("resolveStateDir uses a temp-backed per-workspace directory", () => {
   const workspace = makeTempDir();
-  const stateDir = resolveStateDir(workspace);
+  const previousPluginDataDir = process.env.CLAUDE_PLUGIN_DATA;
+  delete process.env.CLAUDE_PLUGIN_DATA;
+
+  try {
+    const stateDir = resolveStateDir(workspace);
 
-  assert.equal(stateDir.startsWith(os.tmpdir()), true);
-  assert.match(path.basename(stateDir), /.+-[a-f0-9]{16}$/);
-  assert.match(stateDir, new RegExp(`^${os.tmpdir().replace(/[.*+?^${}()|[\]\\]/g, "\\$&")}`));
+    assert.equal(stateDir.startsWith(os.tmpdir()), true);
+    assert.match(path.basename(stateDir), /.+-[a-f0-9]{16}$/);
+    assert.match(stateDir, new RegExp(`^${os.tmpdir().replace(/[.*+?^${}()|[\]\\]/g, "\\$&")}`));
+  } finally {
+    if (previousPluginDataDir == null) {
+      delete process.env.CLAUDE_PLUGIN_DATA;
+    } else {
+      process.env.CLAUDE_PLUGIN_DATA = previousPluginDataDir;
+    }
+  }
 });
 
 test("resolveStateDir uses CLAUDE_PLUGIN_DATA when it is provided", () => {