fix(test): first cross-platform run of the wave's tests — Linux tmp portability + Windows-lane truthfulness

Four platform holes from the lanes' first full run over the v1.67 tests:

- uninstall neutral-root fallback hardcoded /private/tmp (macOS-only) and
  ENOENT'd on Linux CI, where the shard TMPDIR is the gstack-containing
  path that forces the fallback — now realpath'd literal /tmp.
- uninstall's kept-and-listed assertion demanded a backslash path on
  Windows while the bash uninstall prints POSIX paths — now
  separator-insensitive.
- setup-rerun's IS_WINDOWS=0 sub-case and the iron rule's force-restart
  consent path are Unix-shaped by construction (Git Bash ln -snf copies
  without Developer Mode; the consent path boots a real replacement daemon
  the browserless Windows lane cannot host) — gated off win32 with the
  reasons in place; the Windows-relevant halves still run there.
- codex-under-codex-detection drives rendered bash under a hardcoded POSIX
  PATH, so every case saw empty output on Windows — moved to
  KNOWN_WINDOWS_INCOMPATIBLE with the run receipt.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

browse/test/busy-daemon-iron-rule.test.ts

@@ -177,6 +177,12 @@ describe('#2219 iron rule (CLI integration)', () => {
   }, 45_000);
 
   test('wedged-alive daemon + --force-restart IS killed (explicit consent path)', async () => {
+    // Unix lanes only: the consent path must boot a REAL replacement daemon
+    // to answer the command, which the secretless/browserless Windows lane
+    // cannot do (no Chromium install), and the teardown relies on setsid
+    // process-group semantics Windows lacks. The Windows-relevant half of
+    // the iron rule — busy → refusal, never an implicit kill — runs above.
+    if (process.platform === 'win32') return;
     const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'browse-iron-'));
     const stateFile = path.join(tmpDir, 'browse.json');
     const daemon = await startWedgedDaemon();