test(smoke): smoke tests do not cover FTPS (implicit or explicit)

gh issue create --title "test(smoke): smoke tests do not cover FTPS (implicit or explicit)" --label "test,audit,priority:low" --body "## Finding

tests/smoke.sh runs the action against a plain FTP server only. FTPS scenarios (03 and 04 in the integration suite) are not exercised by the smoke gate. A FTPS-only regression could pass smoke and break in production.

## Affected code

- tests/smoke.sh
- (maybe a new tests/smoke-ftps.sh)

## Reproduction

1. Inspect tests/smoke.sh: no FTPS test case.

## Suggested fix

Add a smoke test that runs the action with INPUT_FTP_SSL=true and a self-signed cert. Or add a separate tests/smoke-ftps.sh target and wire it into the Makefile.

## Source

F2 audit 2026-09-03 (tests audit). Reporter: subagent-pekodbj7.

## Related

- Part of EPIC #[epic-number]
- Closes: #NONE (no existing issue)
- Related: #120 (FTPS integration coverage — closed, superseded by current scenarios)"