Bumps @version to 0.2.0 and assembles the five unreleased changelog.d
fragments (sp-1gn, sp-3kk, sp-6ac, sp-km3, sp-q8z) into a dated 0.2.0
section, deleting them in the same commit as changelog.d/README.md
prescribes.

Minor rather than patch: 0.1.3 shipped no library code, and this
version adds a public module (StatifierPersistence.Driver), opaque run
metadata across Runs/Storage/Adapter with migration V02, and the
:blob_type option. For a 0.x package that additive surface is the
minor arm; the repo's own 0.1.1-0.1.3 patches were a fix and two docs
releases.

Prep only: no tag, no publish, no hex task - those stay the
operator's.

Refs: sp-gle