A coarse advisory lock so two git-stk processes never run state-mutating
commands at once. Git locks its own index and refs, but not git-stk’s
multi-step orchestration (snapshot, rebases, metadata, provider calls), so
a concurrent run could clobber the undo snapshot or half-rewrite the stack.
The managed blocks in review descriptions: the user’s description, the
issue-closing link, and the stack-overview ledger ([ledger]), all
built on marker-delimited [sections].
Stack metadata: the branch.<name>.stkParent/stkBase annotations and
the structural queries built on them. Navigation lives in [nav], the
rebase engine in restack.
Semantic terminal styles. Styled lines must be printed through
anstream::println!/eprintln!, which strip color for pipes, NO_COLOR,
and consoles that cannot render it.