Bumps the version to 0.2.0 for the invoke-job dedup key change
(ADR-0003, PR #26): invoke jobs are now unique on
{scope, invoke_id, macrostep} rather than {scope, invoke_id}. That
is an observable behavior change - jobs that previously deduped
across macrosteps no longer do - so a 0.x minor bump, not a patch.

Promotes changelog.d/sob-76d.md into the [0.2.0] section and deletes
it, plus the stale changelog.d/sob-cxw.md whose content already
shipped in [0.1.1]. Flips ADR-0003 to accepted, dated by the
operator's merge of PR #26.

Full mix quality green (86/86, 95.3% coverage).

Refs: sob-u1j