[orsissimo]

Summary

• Omit the post-process driver from SWARM_AGENTS when post_process is absent or null, so image builds do not install a CLI that no container runs.
• The code owner identified this driver fix as independent in Embedding contract for claude-swarm #115.

Changes

• launch.sh: add the post-process driver only for non-null sections, including empty objects and sections without a prompt.
• tests/test_launch.sh: add four cases in section 38 for absent and null sections, an unused top-level driver, and a configured post-process using the default driver.
• CHANGELOG.md: document the fix under Unreleased.

Self-review checklist

• This PR addresses a single concern (why?). If it covers multiple independent changes, I've split them into separate PRs.

Test plan

• tests/test_launch.sh: 234 passed. With master's launch.sh, the absent, null, and unused top-level driver checks fail; the configured default check passes both ways.
• ./tests/test.sh --unit: macOS Bash 3.2.57, 1388 tests; Ubuntu 24.04 Bash 5.2, 1400 tests. Each run covered 13 files with 0 failures.
• shellcheck -s bash --severity=warning launch.sh tests/test_launch.sh: clean.
• ./tests/test.sh --all: not run; requires an API key.

[moodmosaic]

Same here, @orsissimo, if you can rebase 🙏