[Feature]: Stop output duplications

[nircoe]

Piped or redirected output (e.g. CI logs) printed a full grid frame on every test start and end, not just at the end.
It now prints once, in the final summary; interactive terminal output is unchanged.

• Gate GridTestListener's per-event grid redraws on stdout interactivity, so piped or redirected output only redraws once, in the final summary
• Add a regression test asserting non-interactive output contains exactly one grid frame
• Document the interactive vs non-interactive output behavior in the README, docs/ARCHITECTURE.md, and the basic example's README
• Fix crash example to skip its intentional crash tests by default while still crashing under its --run-segfault/--run-abort/--run-divbyzero/--run-crash-suite flags