Release v0.3.0

build: pin sibling refs to v0.2.0 for reproducible v0.2.3 checkouts

The original v0.2.3 versions.cmake auto-derived sibling refs as
master, so building this tag fetched whatever sibling master happened
to be at fetch time. Backport the three-tier precedence logic from
develop (cmake -D > versions.env > derived) and pin all three siblings
to v0.2.0, which matches the sibling state that was on master when
v0.2.3 was originally tagged (Apr 3 2026).

This is a tag-rewrite for reproducibility; the original v0.2.3 commit
is preserved as the parent.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

build: pin sibling refs to v0.2.0 for reproducible v0.2.2 checkouts

The original v0.2.2 versions.cmake auto-derived sibling refs as
master, so building this tag fetched whatever sibling master happened
to be at fetch time. Backport the three-tier precedence logic from
develop (cmake -D > versions.env > derived) and pin all three siblings
to v0.2.0, which matches the sibling state that was on master when
v0.2.2 was originally tagged (Apr 3 2026).

This is a tag-rewrite for reproducibility; the original v0.2.2 commit
is preserved as the parent.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

build: pin sibling refs to v0.2.0 for reproducible v0.2.1 checkouts

DEPENDENCIES_VERSION used to be set to "master", so building this tag
fetched whatever sibling master happened to be at fetch time. Pin to
the sibling v0.2.0 tag, which matches the sibling state that was on
master when v0.2.1 was originally tagged (Apr 1 2026).

This is a tag-rewrite for reproducibility; the original v0.2.1 commit
is preserved as the parent.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

chore: prepare 0.2.0 release

Release v0.1.0