Assert boot screen renders, not just absence of fatals

The previous smoke test and e2e test both checked for known error markers
("Fatal error during startup", etc.). That misses anything we didn't
think to add — novel error messages, silent crashes, hangs, segfaults
that produce no stderr.

Switch both to a positive signal: assert the binary actually rendered a
known boot screen. If something goes wrong we don't anticipate, the
boot text never appears and the test fails with a clear "binary never
reached a known boot screen" diagnostic. Negative pattern matches stay
for clearer error messages on regressions of bugs we've already seen.

- cli/scripts/smoke-binary.ts: gate pass/fail on at least one of N boot
  signals appearing in stdout/stderr (chat surface header, login modal,
  freebuff queue states, freebuff country-block screen, chat input
  prompt). Verified locally: passes on real binaries, fails on a stub
  that hangs without rendering.

- freebuff/e2e/tests/startup.e2e.test.ts: wait for the FREEBUFF ASCII
  logo's F+R crossbar pattern (`█████╗  ██████╔╝`). The logo renders
  for every valid boot state — including the country-block screen that
  GitHub Actions runners hit because their egress is flagged as
  anonymized network — so this assertion survives the geo gate that
  was tripping the previous "Pick a model to start" wait.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>